Cultivated plant globalization

Introduction – Cultivated Plant Globalization

Biological globalization – the historical influence of humans on the redistribution of the world’s plants and animals across the surface of the Earth – is usually considered from the perspective of its economic utility and consequences. The emphasis has also been short-term, reflecting regional and political and economic interests.

The quote by botanical historian William Stearn at the head of this article draws attention to the simple human desire to beg, borrow, or steal whatever nature has to offer. We look back today at a process of discovery and redistribution, the equalizing and homogenizing of nature’s plant bounty that has been going on throughout history.

At the time of the Roman Empire plants from foreign lands – fruits, vegetables, spices, medicines, and ornaments – were paraded triumphantly through the streets as trophies of war and exploration. These were plants that could change the lives of every citizen as new foods, crops, tastes, exotic beauty and more. Today, those with access to world trade can obtain anything that is on offer. We live at a time when the plundering and sharing of the world’s beneficial plants is nearing completion.

It is now time to provide a Plant-People Big History account of how this process – so crucial for human survival, flourishing, and wellbeing – took place . . .  and to consider its biological, environmental, and cultural implications for the future.

Despite its profound consequences for humanity, the historical redistribution of plants has received little long-term consideration. We are well-informed about individual cases – plantation crops like tea, coffee, cotton, and sugar but there is surprisingly little general information about the place of plants in global changes in land use, the relative proportions of wild and cultivated plants (and cultivated plant floristics in general), global trends in urban plant use, and even a simple historical overview of this process at the global scale.

This article presents a brief historical account of the human redistribution of plants over the widest possible scales of space and time . . . the global exchange of plants over the course of human history.

Only in recent times has technology (satellite imagery, photogrammetry etc.) become available to assess and monitor variables on a global scale. At a broad scale the investigation begins with our best assessment of human influence on land use over time.

Context

We are currently within a geological epoch called the Anthropocene, a time of unprecedented human influence on the biogeochemical cycles of planet Earth. Changes in plant geography are a key indicator of this trend as ever-increasing areas of land and natural vegetation are appropriated to provide the food and other resources needed to sustain the growing human population. This humanization of nature has been accompanied by a corresponding increase in global plant homogenization and extinction (Heywood 2017).

Our desire for a sustainable future requires the minimization of negative environmental, social, and economic impacts of globalization and to this end we must understand the historical processes that gave rise to the current situation.

This article sketches the historical geopolitical circumstances that have influenced today’s cultivated plant geography and then describes in more detail the globalization of key economic plant groups.

Global land use

Global changes in human population and its land use (with its impacts on climate, ecosystems, biodiversity, and the functioning of the Earth’s long-term biogeochemical and biogeophysical systems) has increased over time and is now recognized as a transition into the Anthropocene. Only recently has there been a concerted effort to understand the causes and consequences of Earth’s anthropogenic transformation with the historical global mapping of human population densities, built structures and infrastructures, irrigation, crops, livestock grazing, and other patterns of human-altered vegetation cover. A first attempt to integrate global datasets into a single indicator (on a scale of 0 to 100), was The Human Footprint of 2002.^[14]

In 2020, Anthromes 12K was introduced as the first global historical anthrome maps for the 12,000-year period from 10,000 BCE to 2015 CE^[15] based on the latest HYDE 3.2 (History of the Global Environment, HYDE) database.^[16]

Dense settlements: Urban and other nonagricultural dense settlements
Villages: Densely populated agricultural settlements
Croplands: Lands used mainly for annual crops
Rangelands: Lands used for pasture and livestock grazing
Seminatural lands: Inhabited lands with minor use for permanent agriculture and settlements
Wildlands: Lands without human populations or substantial land use

10,000 BCE to 2015

In 10,000 BCE, Earth’s terrestrial surface consisted entirely of Seminatural (~60%) and Wild (~40%) land. By 2015 CE Used anthromes covered about half of Earth’s land, with the remainder Seminatural (~24%) and Wild (~26%). This 12,000 year period encompasses the establishment and spread of agricultural and urban societies around the world (see HYDE 3.2). The first Dense settlements and Rangeland appear c. 8,000 BCE, Croplands c. 7,000 BCE, and Villages c. 6,000 BCE. However, the global extent of Used anthromes did not reach 1% of Earth’s land area until around 2,000 BCE (0.3%) and 1,000 BCE (1.4%). By 1 CE, dense settlements, villages, croplands, and rangelands are present across substantial areas of Mediterranean Europe, The Middle East, Africa, and East Asia (Figure 4). From their first appearance, Used anthromes have generally increased over time, covering 5% of Earth’s land between 800 and 900 CE, 10% by 1700 CE, 25% by 1880, and 50% around 2000 CE. This long-term transformation of Wild and Seminatural anthromes into Used anthromes has proceeded fairly uniformly until accelerating in the late 1800s. During this time of accelerating land use, between 1800 and 2000 CE, about 15% of Earth’s remaining Land were converted to Used and Seminatural anthromes, and more than half of Earth’s Seminatural anthromes were transformed into Used anthromes, only slowing down near the end of the 20th century. In the 15 years from 2000 CE to 2015 CE, the most recent year that Anthromes 12K data are available, anthrome changes were relatively minor, the largest being an approximately 1% decline in Rangeland anthromes.

Geopolitics, transport, technology

Cultivated plant geography has tended, like much history, to follow in the wake of the rich and powerful. Geopolitics, the rise and fall of empires and the desire to accumulate resources within their boundaries, while obtaining additional ones from without, can account in broad terms for plant redistribution across the planet and clearly this has been strongly influenced by access to transport and technology. Remembering, of course, that the story of history comes to us from the pens of the powerful and that there are also local and informal networks of exchange that can be easily ignored.

Plant geography

Plant geography (floristics) is traditionally approached by studying the biotic and abiotic factors that influence the ecology and distribution of wild plant populations growing in natural landscapes. But in today’s world plant distribution is increasingly about cultural landscapes and cultivated plants whose distribution is more a consequence of human social, political, and economic history.

So, why is the distribution and composition of the world’s cultivated plants as we find it today?^[13]

A global redistribution of plant resources

Histories have tended to take regional perspectives of environmental change of this kind, so we are relatively new to the assumption of a global perspective. This is no doubt enhanced by the fact of globalization – that we have now entered a phase of history in which the world’s plant resources are, in a practical sense, available to all: facilitated by rapid long-distance international trade, refrigeration, and technology that can create artificial climates on a grand scale.

Today, with the wisdom of hindsight, we realize that there has been an inevitability about this process of cultivated plant globalization. Our task is to uncover the reasons why this global homogenization of cultivated plants (the global plant resource) happened the way that it did. What were the geopolitical historical forces in operation; what factors influenced plant selection; why did some countries display a propensity for plant transport and distribution and not others; what were the relative influences of history, geography, biology, politics and culture, ecology, technology, transport systems, and so on; what were the major periods and patterns of transfer and exchange; and what have been the advantages and disadvantages of this process that we might take into account for the future management of global vegetation?

We are still neophytes in the study of cultivated plant geography, partly because major changes have occurred in relatively recent times. What have been the key determinants of today’s global distribution of cultivated plants?

Studying cultivated plant geography confronts us with all the difficulties of biological systems. Should our approach be historical, cultural, biological, ecological, social, even political?

There is a further pair of interconnected dimensions to be considered. First, the criteria defining plant transfer, the three selected here being: numbers of species (successfully introduced); area of land occupied, and direct environmental impact (influence on provision of Ecosystem Services). And, second, the economic, social, and indirect environmental influences and consequences at work. Direct environmental impacts are physical impacts on the land and its organisms: indirect impacts relate to resource consumption and waste. This synthetic approach provides us with an overview.

Another approach would be cumulative, extending our knowledge by comparative analysis of individual plant biographies of plant commodities.

Our focus is cultivated plant geography and since we are primarily concerned with actual plants and their distribution not possibilities then biological determinants become of less significance than human agency.

Commonfolk travelled with seeds. Australian settlers engaged in a black market of natural history specimens.

Ambrosi, M. 1997. The Wild and the Sown: Botany and agriculture in Western Europe, 1350-1850. Cambridge University Press: Cambridge.
Brockway, L. 1979. science and Colonial Expansion: The Role of the British Royal Botanic Gardens. Academic Press: London.
Grove, R. 1995. Green Imperialism.
Griffiths & Robin
Flannery The Future Eaters. An environmental history of Australia.

The separation of the historical and scientific domains in academia impede research.

We need quantitative estimates of the relative impacts of the activities of, on the one hand, formal processes recorded as the institutional history of scientists and their organisations which have clear documentary trails and, on the other, informal networks of knowledge, transfer and exchange.

Values: what are the social attitudes and beliefs concerning plant transfer and its effects on the environment?

Criteria used to assess patterns and measures of transfer: numbers of species (successfully introduced); area of land occupied, and environmental impact (influence on provision of ecosystem services). Can we detect economic, social, or environmental patterns in this process?

Temperate agriculture depended on suitability for both plants and animals in Australia, New Zealand, South Africa, Argentina and Uruguay.

The interpolation of cultivated plants into the natural vegetation of the planet has been largely a consequence of human-determined factors (although the appropriate environmental conditions are clearly a pre-requisite). For convenience, the human dispersal of cultivated plants has been divided into four major historical phases: the Agricultural Revolution, the development of Bronze Age urban civilizations and trading networks, the intensification of commercial links between East and West, and the Great Divergence. Also for convenience the kinds of plants being dispersed during these historical phases have been divided into five economically- and socially-significant groups: cereals and staple crops; spices and medicinal plants, horticultural crops, timber trees, and ornamental plants. To this may be added the recalcitrant category of unwanted plants or weeds.

We have selected three ways of measuring plant transfer: numbers of species (successfully introduced); area of land occupied by the new introductions; and direct environmental impact (direct impact on environments). The historical dimension concentrates on economic, social, and environmental factors, the latter as indirect impacts relating to resource consumption and waste. This synthetic approach provides an overview and can be combined with the study and improvement of individual plant biographies.

Historically, key research into the geography of cultivated plants has focused on major crops and their geographic origins (see Vavilov ) and attention to environmental factors like those that determine wild plant biogeography (Good 1964) and the uneasy disciplinary mix of botany and history.

Cultivated plants

The plants we find in cultivation are derived from three major sources: those taken from the wild and which retain their wild characteristics; unusual and desirable variants taken from wild populations for human use; and those that have been selected and perpetuated in cultivation as sports and mutations, or by breeding and genetic engineering. This grouping is sometimes simplified by contrasting plants that are the product of natural selection with those derived by artificial selection (bred or selected for their desirable characteristics) and referred to as anthropogenic plants or cultigens.

Ultimately these are all plants of commercial significance, the desired features might relate to their food value (yield, disease resistance, extended seasonality etc.), their use as a condiment (herbs and spices), for their medicinal properties, as timber, and as garden plants (habit, doubling of floral parts, variegation, colouring and segmentation of leaves, colour of flowers and so on).

These commercial plants can be divided into five groups according to their different modes of cultivation and economic use: cereals and staples (agriculture); herbs, spices, and medicines; horticultural crops (like the nuts, fruits and vegetables of market gardening); timber trees (forestry); and ornamental plants (gardening). In recent times there is a sixth group whose cost must be included and that is the increasing number of naturalised plants that are invading both cropland and nature and whose eradication is extremely expensive.

Means of distribution

Human distribution of plants was a function of trade connecting a web of inland routes to coastal trading hubs. The best known roads and shipping lanes were connected to the major population centres which have changed over time according to political fortune. Imperial capitals have moved and exploration has extended the range of direct trade between peoples.

The speed and efficiency of trade has depended on the development of transport technology – on the land the transition from walking to the use of domesticated animals and carts, trains, cars and planes. On water the use of small cargo rafts, kyaks and canoes on rivers, lakes and canals with the evolution of ocean-going sailing ships, steamships and modern tankers.

There is also a loose evolution of trade that passes from land to rivers and lakes and then to the sea. This appears to have occurred in the West as initially scattered tribal groups coalesced into settled communities along the Tigris, Euphrates and Nile Valleys before trade became centred in the Mediterranean and then Atlantic.

In the West the major population centres were at first centred in the Mediterranean and the Imperial cities of the ancient Phoeniceans, Greece and Rome moving to the Atlantic seaboard cities of Western Europe when a connection established with the Americas in the 15th and 16th centuries.

In West Asia the civilizations emanating from the Mesopotamian core and trade along the Tigris and Euphrates river valleys waxed and waned with sea trade passing along the Persian Gulf, mainly to the west coast of India rich in herbs and spices.

Sea trade in Indonesia and the Pacific, part of a wider network including China and Japan, was connected to the Indian Ocean through the Malacca Strait.

One way of understanding the complexity of maritime trade over time is to work with geographically-linked trading blocs, the Mediterranean Sea, and the Atlantic, Indian and Pacific Oceans.

Much of the distribution of cultivated plants has been part of formal, official and recorded policy. This includes plants distributed by government departments, botanic gardens, academicians and university employees, individual professional collectors and those sent out by horticultural and agricultural societies and official exploration. Among the private (and often unofficial) distributors were nurserymen, entrepreneurs, missionaries, religiosi, adventurers, settlers and private individuals.

GEOPOLITICS OF CULTIVATED PLANT DISTRIBUTION

Prehistory

Anthropogenic landscape change in prehistory was more likely due to the deliberate burning of natural vegetation and interference with animal food chains than with the transport of plant species beyond their natural distribution range.

Agricultural Revolution (c. 12,000-2,000 BCE)

Large scale cultivation of crops in the Neolithic Revolution(see also Aboriginal Neolithic Revolution)
Gradually, across the world, harvesting of wild food plants entailed increasing plant husbandry that took various forms. So, for example, Australian explorer Thomas Mitchell in 1846 observed native grasses arranged in stacks along the Darling River. The seed heads were threshed by Aboriginal womenfolk before grinding stones were used to make a form of bread (Mitchell, 1848).

Centres of origin of agriculture and its spread in prehistory
Fertile Crescent (11,000 BP), the Yangtze and Yellow River basins (9,000 BP) and the New Guinea Highlands (9,000–6,000 BP), Central Mexico (5,000–4,000 BP), Northern South America (5,000–4,000 BP), sub-Saharan Africa (5,000–4,000 BP, exact location unknown), eastern North America (4,000–3,000 BP)
Courtesy Wikimedia Commons – Joey Roe Accessed 28 April 2017

The first substantial human transformation of natural landscapes occurred at sites of plant and animal domestication. This occurred independently in about ten centres across the world, the earliest in the Near East in about 12,000 BCE. Settled agricultural communities growing mainly cereals, but often other crops as well, sprang up along major river valleys where there were fertile sedimentary soils – the Nile in Egypt (emmer wheat and barley processed into bread and beer), Tigris and Euphrates in Mesopotamia (wheat, rye, barley), Yangtze and Yellow Rivers in China (millet and rice), and the Indus Valley in India and Pakistan (wheat, barley). In Mesoamerica maize was domesticated in Mexico in about 7500 BCE, its use then spreading into North and South America. There is also evidence for small-scale agricultural plantations in highland New Guinea that date back about 10,000 years (taro, banana).

Agricultural practices spread outwards from their centres of origin. In Europe, this was from the Near East along the Mediterranean coast to Italy and the Iberian Peninsula where cereals were established in about 5750 BCE although it took about 8000 years to reach the British Isles and Scandinavia in Europe’s north-west.^[9]

This phase of history, known as the Neolithic Agricultural Revolution, eventually resulted in human communities whose scale and degree of organization made possible the construction of cities and societies whose capacity for conquest, commerce, and technology would ultimately connect the world.

Bronze Age civilizations (c. 4,000-750 BCE)

In one of humanity’s greatest social transformations small agricultural communities evolved into hierarchically governed Bronze Age cities and city-states.

Western cities originated around 4000 BCE and were located in the Fertile Crescent that passed from Egypt’s Nile to the Eastern Mediterranean and Mesopotamia. The Indian Harappan Civilization (c. 3300-1300 BCE), founded on earlier cultures, consisted of numerous settlements along the Indus River, trading with Mesopotamia and producing cotton, wheat and rice, while people of the Chinese Bronze Age (c. 2000-750 BCE), like those living in the Xia Dynasty city of Erlitou in the Yellow River Valley, ate bread and cakes of millet and barley and, as in the West, drank Beer.

Urban living changed, in a profound way, the relationship between humans and nature as material culture became more elaborate, creating fundamental urban spaces and mental categories that remain with us today.

Urban spaces were an expression of social functions and values and special horticultural treatment was often required for: palaces, government, and administration; domestic housing; markets, meeting places, workshops, and entertainment; temples and burial sites; public thoroughfares, parks and gardens. Mostly on the fringes of the cities and beyond were the market gardens, vinyards, and grain fields.

In these cities were the beginnings of gardening and urban design.

The advent of walled cities meant that humans, once a part of nature, now had new mental categories that distinguished between the natural and man-made, wild and cultivated, public and private, formal and informal, sacred and secular, work and pleasure, utility and luxury, and all were applied to the selection and use of plants. From this time on, wild nature would be steadily enveloped by the boundaries and structures created by urban and rural concerns.

Plants were now part of the exchange taking place between urban centres, even taking on a new economic role as secondary products within market economies: olives as olive oil and grapes as wine. Trade had become a driving force in social development as cultures, technologies and plants diffused over ever wider geographic areas.

East-West trade (c. 3500 BCE-1500 CE)

Along with the convergence of independently-derived agriculture came a cultural diffusion between the civilizations of East and West which were separated geographically by the barrier of inhospitable Central Asian deserts and plains.

From about 3300 to 1200 BCE a western trading network connected Bronze Age cities of the Eastern Mediterranean Minoans and Mycenaeans to the Near Eastern Cyprians, Egyptians, Hittites, Mitanni, Assyrians, and Babylonians. This trading bloc had a peripheral western side-branch, the Amber Road, which passed along the great European rivers to the North Sea and Baltic. A large New Kingdom Egyptian navy traded grain, wine, timber, olive oil, incense, and perfumes in the eastern Mediterranean, even importing cedar from the region of today’s Lebanon for its shipbuilding. These ships also plied their trade along the Nile, Red Sea, East African, and Arabian coasts on routes that connected to India and beyond.

A brief Dark Age then preceded Classical antiquity (900 BCE-500 CE) with its clashes of Greek and Persian empires. An impressive Persian Royal Road, built in about 500 BCE, extended nearly 3000 km from the city of Susa on the Tigris in the East to coastal Smyrna (modern Izmir in Turkey) in the West. Following a Greek defeat by Persian troops the ancient Macedonian military hero Alexander the Great in 326 BCE penetrated east as far as the Indus River spreading Greek culture into the communities that had evolved from the Mesopotamian core and which had been trading with India for several thousand years. The Greek empire, along with that of the seafaring Mediterranean traders, the Phoenicians, eventually succumbed to what would become the world’s largest empire, that of Rome.

The Silk Road was an ancient divided caravan route connecting China and Japan with the Mediterranean and reaching its height during the Han Dynasty (202 BCE– 220 CE) when China had a monopoly on silk trade with the eager Roman market. A southern offshoot met the Indian Grand Trunk Road and reached further south, linking to the Incense Route which traded frankincense and myrrh across the Arabian Peninsula and Horn of Africa. Overland trade was slow and risky so with improved shipbuilding maritime commerce became more popular. By the first century CE Roman ships were sailing down the Red Sea to access spices from the Indian west coast.

Following the fall of Rome, Christianity took hold across Europe, but by 750 CE the new religion of Islam had completed successful conquests into North Africa, the Iberian Peninsula, the Middle East, and Central Asia up to the boundaries with India and China. Much of the ancient learning of the Classical world, including the accumulated medicinal wisdom, now passed to Muslim scholars. Eastern and southern Mediterranean Europe then gave way to the Muslim Ottoman Turks who built an empire that flourished from about 1300-1600. Muslim and Indian traders now had a firm grip on overland East-West trade routes

In the East, from about 1100 to 1430, China dominated Asian trade with a professional Ming navy based on the Yangtze, and a thriving trade along the Silk Road. This outward-looking policy culminated in seven maritime expeditions between 1405 and 1433 led by Admiral Zheng-he in ships that dwarfed European galleons and penetrated the western oceans as far as East Africa and the Red Sea. Collections of exotic animals, like giraffes, were returned to China but little international exchange was established.

Remarkably, China and Japan then turned inward thus prompting illegal private trade and piracy. In China, ocean-going grain shipments were replaced by canal barges after the Ming Dynasty completion in 1415 of renovations on the vast Grand Canal.

With the fall of Constantinople to the Ottomans in 1453 refugee scholars fled to Italy, settling in Florence and commercial city-states like Genoa and Venice where a Western Cultural Renaissance was stirring.

The Great Divergence (c. 1500-2000 CE)

The dramatic change in world landscapes that has occurred over the last 200-300 years is largely a consequence of what historians call the Great Divergence, a phase of rapid economic growth emanating from Western Europe and spurred on by rapid advances in science and technology, transport and communication, Enlightenment thinking, and an Industrial Revolution. Maritime trade would play a major role in this transition.

Claudius Ptolemy (c. 100 – c. 170 CE), an academic of Greco-Roman Alexandria, had produced a map of the Classical world that served European mariners for about 1300 years, but in the century between 1470 and 1570 in the Age of Discovery, European explorers charted the coastlines of the Atlantic, Indian, and Pacific Oceans to produce a rough semblance of today’s world map, continuing until the task was effectively completed by 1800.

World Map c. 1450-1475
Florentine map reconstituted from that in Ptolemy’s (c.100-c.170 CE) Geographia (c. 150 CE)
Courtesy Wikimedia Commons – Francesco di Antonio del Chierico Accessed 5 May 2017

World Map in 1570
By Flemish Abraham Ortelius (1527-1598), cartographer, geographer, and creator of the first modern atlas Theatrum Orbis Terrarum (1570)
Courtesy Wikimedia Commons – Hello World Accessed 5 May 2017

This period of European colonial expansion began with a search for a sea route to the Spice Islands that would by-pass expensive overland Arab merchant middle-men. First Portugal, then Spain and the Netherlands, developed colonies and trading empires built on the initial desire to monopolize the spice trade. European interests were injected, often forcefully, into foreign lands as trade routes passed to European powers. Spain established a strong trade network across the Atlantic with the New World while the Portuguese commandeered trading hubs in the Indian Ocean and Far East. Much of the Portuguese trading empire was later seized by the ascendant Dutch during a 17^th century golden age before succumbing, in turn, to the ambitions of France and England in the 18^th and 19^th centuries. In 1605 Clusius, the first director of Leiden Botanic garden, published Exoticorum Libri Decem which was the first account of plants imported to the Netherlands.

Colonial Empires in 1800
Courtesy Wikimedia Commons – Jluisrs & George Tsiagakis Accessed 28 April 2017

Eventually England forged the world’s largest ever empire that reached its peak in the century between the defeat of Napoleon in 1815 and the eve of the First World War in 1914, in an era of critical significance for environmental and economic history, and for the global distribution of cultivated plants.

Map of the world showing the extent of the The British Empire in 1886
British territories coloured in pink
Courtesy Wikimedia Commons Red_Hat_of_Pat_Ferrick Accessed 28 July 2017

During the Great Divergence, colonial European powers introduced European people and institutions to Africa, India, the Americas, Asia, and Australasia in an expansion of Europe that was a contraction of the world (Drayton, 2000, p. xiv). European agriculture was established in the temperate European colonies; tropical crops were exchanged between the East and West Indies to become distributed throughout the tropics; and lucrative plantation crops were grown across the world, but mainly in the Americas. While European-style agriculture, ornamental horticulture, and silviculture were exported to these ‘Neo-Europes’ (Crosby, 2004) garden plants were being imported to Europe by means of trade and eager plant hunters, explorers, missionaries, and scientific collectors.

Between 1650 and 1850 the world population doubled, increasing demand on all the world’s resources, including the need for food, forest products, and garden ornament. The Industrial Revolution, energized by fossil fuels, provided steamships, railways, automobiles, and planes, to open up inland regions of all continents to further development. Then after World War II, the world entered a yet more intensive phase of globalization and economic activity, the Great Acceleration when, in the short period between 1950 and 2000 the world population again doubled and America became the leading world power.

The Great Divergence
Graph showing estimates of European and Asian per capita GDP in 1990 between 1500 and 1950 indicating the explosive economic growth of European nations from the early 19th century
Courtesy Wikimedia Commons Semhur Accessed 28 April 2017

Human population growth in the industrialized world has now slowed, being greatest in low-income countries, but the consumption of plant resources, by developed countries especially, weighs heavily on the environment.

GLOBALIZATION OF ECONOMIC PLANT GROUPS

We have distinguished six historically important economic plant groups: cereals and staple crops, spices and medicinal plants, horticultural crops, timber trees, ornamental plants, and naturalized plants.

Globally there are about 3000 known food plants of which about 150 have been extensively cultivated and traded. However, about 90% of the human diet consists of around 15 species and, of these, only four (wheat, rice, maize, and potatoes) make up much more than half of the world’s food supply.

Agricultural cereals & staples

Staple foods are those that make up the bulk of peoples’ diet, the main ones being cereals and root crops like potato and taro and, in a few regions, legumes.

Immense areas of natural vegetation, on all habitable continents, have been replaced by agricultural plants, the transition occurring over many millennia and accelerating in step with the demands of the increasing human population.

Chinese peasants were working the rice-paddies of Central China in 6000 BCE (the likely region of domestication of wild rice). By 1000 BCE it had found its way to India and Sri Lanka, then to northern Africa and southern Europe, to be subsequently transported to the New World by early European settlers. Similar stories of geographic diffusion apply to all the common crops.

After the Neolithic Revolution, farming practices in Europe became more widespread and efficient under Roman administration. At the height of its empire Rome was the world’s largest city with a million residents and, even though a farming nation, wheat was imported across the Mediterranean from Carthage to achieve the complimentary daily ration of bread promised to its citizens. Distant bulk trade in staples had thus now become a necessity for urbanised empires.

The spatial impact of agriculture on the land, and the kinds of plants cultivated, has been greatly affected by technology. In about 1300 across the world lifestyles were similar as most people, except forof the ruling elites, toiled on the land. Worldwide today less than 5% of people are employed in agriculture, a consequence of the Industrial Revolution when people moved from the land to the factories in the cities as the muscle of men and horses was replaced by fossil-fuel-powered machinery.

In England, this social transition was most evident during Queen Victoria’s reign from 1837 to 1901 as scientific and industrial expertise was harnessed to convert a predominantly self-sustaining rural society into an urban industrial society. Over this period, the population nearly doubled from 13 to 24 million. By 1900 the British Empire controlled about a quarter of the world’s land surface and a quarter of the world’s population. Despite a program of land reclamation in the early 18th century about a half of England’s food was now imported (along with other resources), from its colonies.

Mostly in the 19th century, in a series of European colonial land grabs (often involving removal of indigenous people and biota), vast areas of the world’s arable land were taken up for agriculture including: eastern and south-western Australia, Tasmania, New Zealand, the Great Plains of the United States, Canada, also parts of Africa, Argentina, Brazil, central India, and elsewhere. The 18^th and 19^th centuries were a second major phase in the commodification and globalization of plants after the Neolithic Revolution.

Further global food demand was addressed with a Green Revolution (c.1930-1960) when, under large-scale industrial agriculture, many family farms across the world were converted to vast corporate super-farms growing high yield and genetically-engineered varieties.

Imported agriculture also brought unwanted pests, diseases, and invasive organisms that spread out of fields, into rivers, and along roadsides, eventually finding their way into forests and wild vegetation.

Staple crops have had a greater impact on humanity than any other plants. They have provided the life-sustaining energy needed for growth, but their cultivation has made massive demands on the world’s resources while creating irreversible changes to ecosystems. There is more than a grain of truth in the claim that crops have domesticated humans.

Spices & medicinal plants

See also the Silk Road, Silk & Spices, Spices, Botany of spice plants, and the Spice Route
Perhaps surprisingly, it is not food plants but herbs, spices, and medicinal plants that have held a special fascination for humanity. Aromatic and psychoactive plants had mystical properties that connected humans to the gods and spirit world. Along with plant medicines they were, in traditional societies, administered by some kind of ‘medicine man’ – replaced in urban societies by religious and intellectually wise men – priests, apothecaries, physicians and, more recently perhaps, scientists.

Incense, frankincense and myrrh, sourced from the wild, had special religious significance. The tradition of incense-burning, popular in ancient Egypt and Babylon, was also practiced in the ancient civilizations of India and China, and is still important in religious rituals today. Opium was traded in antiquity between plantations on Cyprus and the Egyptian pharaohs in an ancient drug trade. The transparent glassy golden orange amber (obtained as resin from coniferous trees of northern Europe) was associated with the Sun and emitted a pine-like aroma when rubbed or burned.

India, the land of spices, had attracted ancient Babylonians, Assyrians, and Egyptians to the Malabar Coast, the southwest region, Kerala, being a centre for land and sea trade from East and West. Many of these Indian and Far Eastern tropical spices were used as condiments and would become pivotal in world trade and global politics, they included: cardamom, cassia, cinnamon, cloves, mace, nutmeg, pepper, turmeric and, to a lesser extent, ginger, henna, sandalwood, and sesame.

In the West leafy aromatic herbs (origano, parsley, rosemary, sage, thyme etc.), many Mediterranean in origin, were garden favourites. Spices, which were sourced from root, stem, bulb, bark, resin, or seeds were mostly native to the Asian tropics, with chillies, pimento, and vanilla sourced from the Americas (there are notable ‘western’ exceptions such as caraway, cumin, dill, fennel, garlic, juniper, liquorice, mustard, and onion).

Western medicine can be traced from ancient Egypt to the Greek physician Hippocrates and Greco-Roman physician Galen. In the Middle Ages the tradition was perpetuated among scholars of the Islamic world and in the Christian monastery physic gardens that pre-dated the first university medicinal ‘botanic’ gardens of sixteenth century Renaissance Italy when botany was extricating itself from its medicinal origins. Equally influential medicinal plant traditions existed in the ancient Indian and Chinese cultures.

Being controlled by rulers, the wealthy, and religious leaders, spices symbolized social status, becoming prestige luxury goods.

The European Age of Discovery began with a spice race between the dominant European naval powers of the time, Portugal and Spain, as they attempted to find a sea lane that would by-pass the Arab merchants controlling the overland Spice route. The goal was the source of nutmeg and cloves but their location on the Indonesian Molucca islands of the Banda and Molucca Seas was an Arab trade secret.

Seafaring trade had long connected India with South East Asia and the islands of the Indonesian Archipelago. Indonesian trade was, from the 8th to the 12th centuries, in the hands of the Sumatra-based Buddhist-Hindu Srivijaya culture subsequently taken over by the Mohavajit Empires. Arab, Persian, and Indian traders had ensured the creation of sultanates in the region so by the 15th century Malacca, on the Malay Peninsula, was an entrepôt for Muslim trade between the Indian Ocean, Java Sea, and South China Sea. Further eastward in southern Sulawesi was Ujung Pandang (Makassar) a multi-racial multi-religious spice entrepôt.

Sailing westward Spaniard Columbus stumbled into the Bahamas, Hispaniola, and Cuba in 1492 and was convinced that he had reached the Spice Islands. This voyage had major ramifications, opening up the Atlantic to commerce between the Americas and northwest Europe.

Sailing eastward the Portuguese had rounded the African Cape (Diaz, 1488), then tracked the African east coast before crossing the Indian Ocean to the Malabar coast at Calicut (Da Gama, 1497) then on to Malacca in 1498. In 1500 Lisbon was the spice hub of Europe, but access to nutmeg and cloves was indirect until the Spice Islands were finally located in 1511. By 1515 Portugal had established local trading hubs and coastal forts that commandeered the trade from Lisbon to India, Sri Lanka, Malacca, and the Moluccas and in 1517 trade with China began. The cloves of Moluccan Tidore could now be exchanged for the silver obtained in Mexico and Peru.

Magellan’s Spanish expedition of 1519-1522 was the first to circumnavigate the globe, proving beyond doubt that the world was a sphere. In so doing he had experienced the spatial limits of the world, the physical reality of a finite planet. Back in Europe this helped generate the desire to begin an inventory of the world’s biological resources, initiating an era of taxonomy and, in the case of plants, flora-writing.

China discouraged trade with Europe at this time but an opportunity arose when, in 1557, a Portuguese naval base was permitted in Macao. Ships now brought spices from Malacca and traded silks and gold with southern Japan. Gradually maritime trade with the West increased.

To control Malacca and Makassar was to control the spice trade. In the 16-18th centuries first Portugal then the Netherlands seized these ports, the Dutch East India Company building its own trading hub, Batavia (today’s Jakarta) in 1619.

France and England then combined strategic and economic interests with Enlightenment ideals when they launched voyages of scientific exploration to the Pacific and East Indies, England taking possession of the Australian continent and many of the surrounding islands. Portuguese, Dutch, and subsequent British influence in the region still remains together with the Spanish Philippines and its trading centre in Manila.

Spice interests in the Far East eventually declined as plants were smuggled away and grown elsewhere as trade quickly diversified.

Herbs, spices, and medicinal plants have occupied little of the world’s land space. Their significance lies in the role they have played within human culture, not least of which being the development of plant science. Spices helped forge trade links between cultures in the ancient world and between East and West along the Silk Road. The quest for nutmeg and cloves was Europe’s first step on the path to the Great Divergence.

Horticultural crops

Bronze Age civilizations had grown an assortment of horticultural crops, sometimes in market gardens. The Bible’s Book of Numbers describes Egypt as ‘the land of Figs, Vines, and Pomegranates’. Pomegranates recovered from archaeological sites had 4 chambers instead of the 6-8 we know today and fruits in general were mostly smaller than those of today (Hawks & Boulger 1928, p. 20).

In the West this tradition was maintained in the Greco-Roman world, the Romans in particular dispersing fruits and vegetables across their empire. Among these plants were almonds, carrots, chestnuts, garlic, globe artichoke, lettuce, onions, and walnuts (Vaughan & Geissler, 1998).

Roman trade included goods passing along the Silk Road. We know that it was not only luxury spices that moved along this corridor but ideas and even disease. Some crops diffused outward in both directions from the centre of the European continent – like apples, carrots, cotton, sesame, lemon, and possibly garlic and the popular domesticated onion. Passing westward from East Asia were the cereals rice, buckwheat, and millet together with the fruits almond, peach, and some citrus. The eggplant (aubergine) first cultivated in India was subsequently used in both China and as a staple of the Islamic world. From the West passing to China were alfalfa, broad beans, peas, spinach, turnips, different citrus and watermelon (Vaughan & Geissler, 1998). Both wheat and barley arrived in China around 1500 BCE to be used mostly in the north in bread, noodles, and dumplings called manti which appear to be a creation of the Silk Road.

During the Middle-Ages Islamic culture controlled trade through the Middle East and much of the Mediterranean region including the Iberian Peninsula, so Arab merchants were the primary agents of worldwide plant exchange at this time. several introductions to Europe arrived via Moorish Spain probably including the eggplant (aubergine), lemon (possibly Roman), lime, pomelo, rice, Seville orange (possibly Roman), and spinach (Vaughan & Geissler, 1998).

We only have to consider the world’s six major plant-based beverages: beer, wine, spirits, tea, coffee, and cola to realize the social and economic impact of horticultural crops on the world.

Atlantic economy

Following the discovery of the New World and its mineral riches, new trading centres emerged in north-west Europe, West Africa, and the Americas as links in a highly lucrative Atlantic economy. At first this involved just Portugal and Spain as gold and silver obtained in the Americas were used to pay for the silk and other goods obtained from China and the Far East: but the Dutch, French and English soon followed.

The Atlantic economy provided impetus for European colonialism soon diversifying to include timber, and other raw materials, but especially plantation crops and their products. In a clockwise cycle of trade that followed the South Equatorial Current to the Americas and then the Gulf Stream, there were handsome profits at every port of exchange. Goods manufactured in Europe were traded along the African west coast where slaves were taken aboard for the Atlantic crossing to the Americas and Caribbean where they were delivered to the plantations. Plantation products were then loaded up for the journey back to Europe before the cycle was repeated. Slave labour provided products that included tropical cotton, sugar, tobacco, molasses, and rum.

Atlantic Trade
18^th century triangular trade between Europe, the New World, and Africa

Atlantic trade in plant products gathered momentum in the 17th century with sugar plantations in Brazil expanding into the West Indies. Sugarcane, which is native to SE Asia, possibly domesticated in New Guinea around 6000 BCE, had passed in ancient times to India, then to Egypt, Syria, and Arabia, and from there into Europe, including the Canaries, from whence it was introduced to the New World by Columbus in 1493. Sugar beet, bred for a high sugar content, was to become popular in the 19th century contributing to about one third of the world’s sugar supply.

The socially fashionable tobacco was first grown in plantations in Virginia then Maryland. By the 1830s cotton plantations in southern USA were feeding the hungry textile factories in Britain’s industrial north.

coffee initially cultivated in Portuguese Brazil was later grown by the British in Kenya from about 1895 to the 1920s. Cocoa growing naturally in Central America was established by the Portuguese in Brazil but then by the British in West Africa especially in Ghana and the Ivory Coast where palm oil was also sourced. To these products we can add the Rubber plant from Brazil, quinine from Bolivia, Ecuador, and Peru, and sisal from South America.

Food crops new to Europe and obtained from South America and the Caribbean included avocado, cashew, cassava, chilli peppers, cocoa, Jerusalem artichoke, Lima bean, peanuts, pineapple, pumpkin, French and runner beans, squash, sunflower, sweet potato, and vanilla – but perhaps most notably the tomato and potato (Vaughan & Geissler, 1998). Old world crops taken to the New World included the apple, apricot, eggplant (aubergine), cabbage, chick pea, citrus, coffee, grapes, mango, olives, onions, peaches, pears, spinach, sugarbeet, and tea. From Africa came sorghum, henna, and watermelons.

Exchange of animals and plants between Europe and the Americas included not only agricultural and horticultural crops but their commensals and diseases in a fusion of Old World and New World biology that we now know as the ‘Columbian Exchange’, named after Christopher Columbus (Crosby, 2004).

Asia-Pacific economy

European maritime exploration had soon secured the Cape of Good Hope as a stepping-stone to the East – not only the Indian Ocean and the spices of Sri Lanka and India’s west coast where the Portuguese established settlements and medicinal gardens, but beyond to the trading networks of East Asia.

Traditional trade in the Indonesian Archipelago was based on rice, copra, sago, and spices. Moving westward were camphorwood, cinnamon, cloves, mace, nutmeg, pepper, and sandalwood which were exchanged for gold and silver, Chinese porcelain and silk, and Indian textiles.

Plants transported from Southeast Asia included the banana, breadfruit, citrus, coconut, sugar, taro, yams, and plantains and, from China, millet and soybean. In the sixteenth century the banana was introduced to the Americas by the Portuguese via West Africa and the Canaries but it would remain an exotic luxury novelty in temperate Europe until the advent of rapid transport and refrigeration in the twentieth century. Asian fibres included hemp and jute.

Enlightenment French and English voyages of scientific exploration in the southern Pacific would take possession of further territories including Australia, Tasmania, New Zealand, and New Caledonia.

The Dutch had established rubber in Sumatra and coffee in Java and Sri Lanka. By the 19^th century it was tea, rice, and rubber that made up much of the cargoes of the powerful Dutch and British East India Companies, made more efficient with the opening of the Suez Canal in 1869. By the 1870s the British Raj in India had had vibrant trading hubs in Madras, Calcutta, New Delhi, and Bombay along with tea and coffee plantations.

Enlightenment scientific interest in economic botany had developed out of Dutch colonial interests in tropical botany with plant hunters, gardeners, and botanists joining voyages of scientific exploration.

Botanic gardens played a major role in the initial discovery, introduction, and distribution of horticultural crops, colonial gardens playing a major role in the success of sugar cane, coffee, tea, rubber, and forest trees (McCracken pp. 137-143). Philip Miller (1691-1771), chief gardener at the Chelsea Physic Garden, excelled in the initial cultivation of melons, paw-paws, and pineapples in glasshouse hot-beds. But novelties and curiosities would turn into major industries. The Royal Horticultural Society’s Plant hunter Robert Fortune in 1848 successfully used Wardian cases to move towards 20,000 tea plants from China to India as a foundation for the Assam and Sikkim tea industries, the Wardian case also being used by the British and Dutch to transport the Quinine Tree Cinchona from Bolivia to Java and India, Rubber Tree, Hevea brasiliensis from South America via Kew to Malaysia and Ceylon, Cavendish Banana, Musa acuminata, from China to Chatsworth Gardens to Samoa, even the Mango, Mangifera indica, as grafted trees transported in the late 1840s from India to Queensland Australia (Keogh, 2017). Keogh (2017) also reports that Berlin Botanic Gardens were playing an increasing role in the trading of horticultural crops between Europe, Africa and New Guinea (Sisal transported from Central America to Africa by the German East Africa Company), while in France the Jardin d’Agronomie Tropicale in Paris had become a French colonial centre for crop research, and Holland’s Leiden and Amsterdam gardens a stepping stone for crops like cinnamon, mango, and ginger on their way to the Bogor Botanic Garden in Java and thence into Asia.

In the course of the Age of Discovery, the traditional botanic gardens changed from medicinal garden to botanic institution, incorporating plant novelties, demonstrating plant classification systems, and contributing to plant inventory through scientific taxonomy, floras, catalogues, and an international seed exchange (active until recent times). In the tropics these gardens were experimental and provisioning stations, holding bays for plant novelties on their way to European gardens and for tropical crops passing between the East and West Indies.

Major European city botanic gardens were administration centres for plant collecting and economic botany in the 18th and 19th centuries. The Jardin des Plantes in Paris introduced coffee to the West Indies from a plant sent to Louis XIV as a gift from the Dutch government in 1714, the plant itself derived in turn from one sent to the Amsterdam Botanic Gardens from Java in 1706. Gardeners and botanists from Kew Gardens in London, under the watchful eye of Joseph Banks (1743-1820), joined Enlightenment voyages of scientific discovery as did those of the Jardin des Plantes in Paris overseen by André Thouin (1746-1824). Rubber plants were cultivated at Kew before distribution to Singapore and Sri Lanka, and Kew was also instrumental in the introduction of quinine to India. Breadfruit was transferred by Britain’s Captain Bligh from Tahiti to St Vincent Botanic Gardens in the West Indies in 1793, intended as a staple food for the slaves in the plantations. Cassava (tapioca) was transported to Asia from South America via the Mauritius Botanic Garden in 1736, and thence to Calcutta Botanic Garden.

Timber trees

Over the long term the world’s forests have undergone natural expansion and contraction in response to ice ages and climate change. Human influence on this natural process began with the Neolithic clearing for agriculture and grazing and we assume heavy deforestation resulting from the human demand for fuel as depletion of woodland around cities is well known from ancient history.

Forests cover about 30% of the Earth’s land surface. About 36% of this area is native forest and 13% is legally protected (World Bank, 2017). Though only about 5% of forests (which cover about 30% of the world’s land surface) consist of timber plantations, a far greater percentage is actively managed, enclosed, or only semi-natural (World Bank, 2017b).

By the 11th century BCE forests around cities in Palestine and Asia Minor (western Turkey) had been plundered. Hills around ancient Athens and Rome were denuded creating erosion problems so that timber had to be sourced from distant locations.

Fernow (2011) noted the usual pattern of forestry development beginning with clearing for agriculture followed by a phase of protection, then more strategic silvicultural techniques including selective logging, enclosure, timber plantations, reafforestation etc. He also reported that Britain, once ‘heavily forested’ , in the early 20th century had forests covering only about 4% of the land as one of the least forested of European countries at that time. This has expanded to about 13% today (Forests Commission, 2017). Australia has lost over 40% of its forests since European settlement (World Bank, 2017). In contrast in Japan human impact on Japanese forests was reduced during shogun rule (1603-1867) and since the end of the 19th century improved forest management has resulted in 68% forest cover.

Tree plantations and forest management practices in the West were established mostly in the 18th century, most notably in Britain and France, but also in the British Empire and tropics. By the 19th and 20th centuries forestry practices were being subject to increasing government control across the British Empire, United States, and Europe.

Modern technology using bulldozers, chain saws, railway networks and logging trucks means large areas can be cleared in very short time, a matter of global concern. Since 2003 the United Nations Food and Agriculture Organization has provided policy advice on sustainable forest management.

Ornamental plants

All cultures have admired plants for their beauty. From antiquity we know of a few plants that were given special status: roses were popular in ancient Egyptian, Greco-Roman, Persian and Islamic cultures. Then there is the Chrysanthemum of China and the two sacred lotuses, one of Egypt (Nymphaea), the other of India (Nelumbo).

However, ever since Greek philosopher Theophrastus it has been Europeans who have indulged a scientific, not just utilitarian and aesthetic, interest in plants. This intellectual curiosity has been combined with an idiosyncratic acquisitiveness as plant collections have accumulated in herbaria, museums, botanic gardens, plant nurseries, and home gardens.

Though gardens date back to the Bronze Age in the West, the Romans took garden aesthetics to new highs. But the fascination with plant trophies, the ‘beautiful, curious, and new’ began in earnest in the 16th century, accelerating through the Age of Discovery, and culminating in an 18th century plant lust and collectomania sometimes called ‘botanophilia’. This was a movement headed by celebrated personalities like Englishman Joseph Banks and France’s Empress Josephine Bonaparte. The wealthy and influential in Europe all wanted a share of the world’s botanical bounty but, as with the spices before them, it was some time before these plants would trickle down to the lower social strata. The populist democratic horticulture we know today did not arrive until after World War II.

Parks and gardens take up little planetary space but they incorporate many different kinds of plants. We can get an idea of the botanical scale of this by following the global plant stocktake that has taken place over time.

We have inherited from antiquity just a few key plant inventories, each one adding to the names of the past. They begin with medicinal plants listed on Egyptian papyri (c. 2000-1000 BCE) and the works of Hippocrates (c. 460 – c. 370 BCE), followed by the more general listings produced by Theophrastus (c. 371 – c. 287 BCE) and Pliny the Elder (c. 23-79 CE), and the Materia Medica of Dioscorides (c. 40 – 90 CE). At the time of the Roman Empire about 1,350 different plants had been recorded in the West.

Wild plants

During the 16^th and 17^th centuries in Europe, botanical science had emerged from its medicinal origins and was laying the foundations for plant inventory – its system of classification and nomenclature. Botanists were describing new species, speculating about the possible number of different plants in the world, and publishing lists of existing species – 4,000 in 1613 (Jean Bauhin), and 6,000 in 1623 (Gaspard Bauhin). English botanist John Ray listed some 18,700 different kinds of plants in his three-volume Historia Plantarum (1686-1704). Frenchman Louis-François Jauffret estimated in 1790 that there were at that time about 25,000 species known to science (Jauffret 1790). In 1753 Carl Linnaeus, Europe’s most renowned naturalist of the 18^thcentury, a few decades before Australian settlement by Europeans, had estimated that the total number of plant species in the world was unlikely to exceed 10,000 (Stearn, 1959).

It was soon apparent that Linnaeus had made a gross underestimate as plants flooded into Europe at the end of the 18th century. Then, between 1829 and 1933 Britain greatly extended existing plant knowledge as Kew botanists published a series of floras (effectively a stocktake of plants growing within the British Empire). They were floras of North America, Antarctica, New Zealand, Tasmania, British West Indies, Sri Lanka (Ceylon), the Cape of South Africa, Hong Kong, Australia, and British India.

Today the total number of naturally-occurring seed plant taxa in the world is estimated at about 374,000 (RBG Kew, 2016).

Garden plants

Among the first books to be printed in the 15th century were the compendia of medicinal and garden plants called herbals in a tradition that lasted from about 1470 to 1670. Most of these borrowed heavily from Dioscorides and plagiarized one-another’s work and illustrations. In 1561 Swiss physician Conrad Gessner in his De Hortis Germaniae Liber had listed about 1000 plants grown in German gardens (Stearn 1984). We can count the 500 to 1,000 species described in herbals as the recorded legacy of cultivated plants bequeathed to the modern world from Classical times (Morton, 1981, p. 175).

Plant exchange between countries has been a two-way process but in the case of ornamental plant species this has taken on a Eurocentric flavour as a flow into Western Europe, beginning in the 16th century with colonial exploration and expansion – part of the accelerating process of globalization. Waves of new plants arrived in gardens as Europe extended its geographic influence outwards. This has been divided into a number of major phases (Stearn, 1965 supplementing the work of Kraus, professor of botany and director of the botanic garden at Halle, east Germany):

• To 1560 – European-Mediterranean Period
• 1560-1620 – Near East (mostly bulbs)
• 1620-1686 – Herbaceous plants from Canada and Virginia
• 1687-1772 – Cape of South Africa
• 1687-1772 – North American trees and shrubs
• 1772-1820 – Australian plants

Stearn increased the number of periods to nine, his additional three periods being:

• 1820-1900 – tropical glasshouse plants and hardy plants from Japan and North America
• 1900-1930 – plants from West China

An additional pair of non-geographic but important categories of cultivated plants can be added:

• 1930s-> – genetics and plant breeding producing new garden varieties
• 1980-> – genetically engineered plants

This account of the phases of ornamental plant introduction to Europe omits to mention the subsequent redistribution of ornamental plants from Europe into to what have been termed the Neo-Europes – those countries that were the products of European colonial expansion and which now cover a large proportion of the world’s land surface: North America, Australia, Tasmania, New Zealand, parts of South Africa, South America, India and numerous islands. These territories have, in turn, exerted their own influence on the world. Taking the Neo-Europes into account gives us a global perspective on the floristics of ornamental cultivated plants.

The focus on European, mainly British, introduction of ornamental plant novelties, with its associated literature of exploration and discovery, can seem a spectacularly one-sided western Euro-British view of plant history (we do not, for example, read books about the intrepid plant hunters of Romania and are poorly informed about the garden plants of non-English-speaking countries). Even so, it does appear to have been the western European nations that did the bulk of the ornamental plant accumulation, the important point is that the garden flora accumulated in western Europe did not make its home there; it was subsequently passed on to the Neo-Europes, those nations within the European sphere of influence (North America, Australia, New Zealand, parts of India and South Africa, SE Asia etc.) and from the Neo-Europes to other parts of the world. Historically gardening has had universal appeal, but the western Europeans were, and still are, of a particularly, if not peculiarly, acquisitive bent.

To 1560 – European-Mediterranean Period

Following the Roman occupation of Europe And into the Middle Ages the construction of gardens for pleasure was infrequent. Those with the resources to maintain ornamental gardens lived in Medieval feudal castles and had little inclination while land outside was difficult to maintain. The few new plants were retrieved largely from western and central Europe and the Mediterranean. What little horticulture was enjoyed existed mostly in the monastery gardens and no doubt exchange would have occurred between these establishments and some new plants were brought back from the eastern Mediterranean during the Crusades.

Emperor Charlemagne c. 800 published a list of recommended plants for monastery gardens in his Capitulare de Villis. Garden historian Stearn points out the Latin and Greek origins of the common names used for this core assemblage of European garden plants used at this time, for example, in Germany, Austria, France, and England. So from the Latin ’cerefolium’ comes the French ‘cerfeuil’, German ‘Kerbel’ and English ‘chervil’; from the Latin ‘foeniculum’ comes the French ‘fenouil’, German ‘Fenchel’, English ‘fennel’ . . . and so on. By the end of the Middle Ages double-flowered and unusual flower colours were appearing in plant collections. An account of plants from this period is given in Harvey (1981).

1560-1620 – Near East & Spanish America

Herbaceous – tulip, anemone, ranunculi, hyacinths, narcissi, fritillarias and irises.

Woody – Horsechestnut Aesculus hippocastanum, Lilac Syringa vulgaris and Philadelphus Philadelphus coronarius.

From Spanish colonies came Tobacco Nicotiana tabacum, Sunflower Helianthus annuus, Century Plant Agave americana, Nasturtium Tropaeolum minus, Tagetes Tagetes patula, Tomato Lycopersicum esculentum, and Potatoe Solanum tuberosum.

Plant introductions to Western Europe came from the Balkan Peninsula and Western Asia as the Ottoman Empire spread over the former Byzantine Empire – Constantinople taken in 1453, Belgrade in 1521 and the outskirts of Vienna in 1529. These included many bulbs and tubers that were both beautiful and distinct from the existing garden flora of Western Europe.
In the 16th century the former castles were being gradually replaced by country estates, in England these were built by nobles made wealthy on Henry VIIIs dissolution of the monasteries.

Only a few of the plants from tropical and subtropical South America could survive harsh winters and the cultivation of others would wait until technology allowed their growth under glass.

1620-1686 – Canadian & Virginian herbaceous plants

Aster tradescantii, Tradescantia virginiana, Rudbeckia laciniata, Oenothera biennis, Monarda fisdtulosa, Campsis radicans, Rhus typhina.

Following Columbus’s encounter with the Americas the French established settlements in Canada and the British in Virginia, both colonists returning ornamental plants to their homelands. The names of several of these plants commemorate British pioneers of plant hunting John Tradescant the Elder (c. 1570s-1638) and his son John Tradescant the Younger (1608-1662) who assembled an impressive collection of North American plants in their London garden at Lambeth.

By the 1730s England was the acknowledged horticultural capital of Europe with the Chelsea Physic Garden holding Europe’s most extensive plant collection. A 1750 preface to a German language edition of Miller’s Dictionary of Gardening (Miller was in charge of the Chelsea Physic Garden and the Dictionary was a monumental compendium of garden plants of the day) declared that: ‘The British are all, more or less, gardeners’ (cited in Wulf, 2009, p. 136).

From the 18th century in England a new affluent middle class of merchants and professionals joined the upper echelons of society in the socially prestigious activity of gardening. This was reflected in the rapidly increasing number of commercial plant nurseries. In the reign of Charles I (1600-1649), London had about five small nurseries and seed suppliers, these numbers rising to around 15 by 1700, and 35 in 1730 when nurseries were starting up in the provinces. In Georgian England (1713-1830) by 1760 there were around 42 nurseries in London and 40 in the provinces including distant places like Edinburgh and Yorkshire. By 1780 printed directories were being produced (Harvey, 1974, pp. 4-6).

In late Georgian England the number of commercial plant nurseries soared. As the Industrial Revolution progressed so too did communication by transport and the printed word, so that by 1839 garden chronicler John Loudon could list 18,000 species cultivated in Britain (Harvey, 1974, p. 128). Similar developments were taking place on the continent and in the colonies. The numbers of new species and cultivars available would continue to climb.

The 19^th century then combined a rapid increase in global population with the successes of industry, along with vastly improved technology, communication, and transport systems all integrated into Britain’s relatively stable and flourishing global economic empire. As a result of inventions like the Wardian case. Nurseryman George Loddiges (1786-1846) ‘… put into circulation over 500 cases to all parts of the globe’ and ‘… it is estimated that in just 15 years William Hooker, director of the Gardens at Kew from 1841 to 1865, imported more plants than in the previous century‘ (Keogh, 2017). Attention was on homeland plant acquisition but clearly plant exchange was in two directions.

Today Britain’s native flora numbers about 1,500 species but since the number of plants growing in the wild totals about 3850 then more than half of these are naturalised aliens. By contrast the different kinds of garden plants alone (including cultivars) numbers well over 120,000 (Armitage, 2015, pers. comm.).

Australia has a flora of about 29,000 species and of this about 13% (~3,750) is naturalised. Of these naturalized plants about 60% are garden escapes.

1687-1772 – The Cape of South Africa

Succulents, bulbs, Pelargonium, Protea and many more.

The spice race to the East Indies was won by Portugal in the early 16th century but the Dutch would assume political and strategic power in Europe through a Dutch Golden Age in the 17th century, consolidating sea lanes by fortifying critical provisioning entrepôts on the way to the other side of the world. Foremost among these was the settlement made in in 1652 on the Cape of South Africa in the world’s richest floristic regions replete with bulbs, annuals and succulents that were a treasure trove for wealthy European gardeners, the tender ones protected by new heated glasshouse technology (orangeries, glasshouses, conservatories).

Though Portugal and Spain had gardening traditions it was mainly the Netherlands and its botanic gardens at Leiden and Amsterdam that set the European trend for the plant collection and gardening that would follow, acquiring plants collected overseas and making a special study of those from the tropics. There was a ready exchange of plants between the botanic gardens of Keiden, Amsterdam, Paris, Chelsea, Oxford and others.

1687-1772 – North American trees & shrubs

This phase of plant introduction resulted from the British colonization of the forested Atlantic seaboard of North America which, by 1700, extended from Massachusetts to Virginia. In England royal forests had been used as hunting grounds, mostly deer parks until, in the reign of Elizabeth I, there was official acknowledgement of their use for timber production (James 1981). There followed a period of exploitation, the timber used mostly for smelting and shipbuilding, especially during the Civil War of 1642-1660. In an appeal to conserve this resource John Evelyn in 1664 published Sylva or Discourse on Forest Trees. This was a source of information on the different kinds of trees available and offering advice on their cultivation. It stimulated wealthy British landowners to extend tree plantings on their estates, not only for timber but for their visual appeal and scientific interest. This period saw the birth of the arboretum as a scientific collection of trees and a new interest in owning a diverse assortment of attractive trees (Stearn 1972).

The American trees proved an exciting addition to country estates, transforming rural landscapes with their different forms and colourful autumn foliage supplementing Britain’s meagre supply of less than 10 native trees.

1772-1820 Australian Plants

Joseph Banks, Daniel Solander, Peter Good
The collections by Banks and Solander on Cooks first circumnavigation of the globe in the Endeavour included those in New Zealand and the east coast of Australia. Among the first were Sophora tetraptera, S. microphylla, Tetragonia tetragonioides, Eucalyptus gummifera and Allocasuarina torulosa. Once the colony of New South Wales was established many plants were returned by residents as well as avid plant collectors. Among the better known collectors were Kew-trained Scottish gardener Peter Good who with captain Matthew Flinders, botanist Robert Brown and artist Ferdinand Bauer made up a formidable trio circumnavigating Australia in HMS Investigator in 1803. Though Good died on the return trip, his collections yielded specimens of Banksia, Beaufortia, Brachysema, Calothamnus, Chorizema, Dryandra, Gompholobium and Hakea.

Australian and South African plants needed special care to overcome the European climate and the appropriate conditions were created by steam-heated pipes in the new glasshouses. There was also a proliferation of commercial nurseries, a few with outstanding facilities such as the London nurseries of Conrad Loddiges and Lee and Kennedy’s Vineyard nursery at Hammersmith, this latter nursery between 1788 and 1794 raising many Australian plants for the first time. Some plants were also raised in France, notably by Empress Josephine. Cultivation of Australian plants by the well-to-do was stimulated by the production of exquisitely illustrated periodicals like Curtis’s The Botanical Magazine . . . , Andrews’s Botanist’s Repository and Edwards’s Botanical Register.

1820-1900 – tropical glasshouse plants and hardy plants from Japan and North America

This was the Victorian era and Industrial Revolution marked by an expanding middle class, improved transport systems, education, and technology, and increased leisure time. The middle class could now indulge time and money in the pursuit of their gardens as had the well-to-do nobility before them. Coal was carried first by canal barges, then railways, to the industrial machinery that was driving economic growth in the British Empire. Grain and meat was imported from productive arable land taken in land-grabs in colonies like America and Australia to feed the rapidly growing population of miners, factory workers and garden labourers.

For the first time glasshouses adopted the use of moist heat that suited the growth of orchids, especially the epiphytes, and other tropical plants, driving plant explorers into the world’s hot, moist forests, pillaging plants for latest horticultural fashion, the steaming luxuriance of the tropical jungle. Novelties were now coming from different vegetation types as well as foreign countries. The money to be made from these plants prompted the more up-market nurseries, like the Veitches of Chelsea, to send out their own professional collectors. This was also the time for houses to proudly display attached and lean-to conservatories.

At the same time plant collection continued apace as a search for hardy perennial plants and trees in North America and Japan. The Royal Horticultural Society sent out Scotsman David Douglas on successful collecting trips, first to eastern North America in 1823 then western North America in 1824 with a rich haul of plants that have graced western gardens ever since.

East India Company agents had returned plants from Canton and Macau in China for many years but Robert Fortune surpassed them all and collections began in the interior.

Japan was accessed only by the Dutch from a small man-made island of Deshima in Nagasaki harbour but German Phillip von Siebold managed to win favours who sent back plants to be grown in the Ghent Botanic Garden (then in Dutch territory) and later came John Gould Veitch of the London Veitch nursery. With the founding of the Yokohama Nursery Company the exchange of plants eased and there was a free flow of plants from Japan into the West.

1900-1930 – West Chinese plants

China, more than any other country, has enhanced western gardens, many of them introduced between 1860 and 1890 by Hance, Henry, David and Delavay.

To these were added many more gathered by the Veitch Nursery collector Ernest Wilson (1976-1930) who, in 1902 returned to England with seeds of 305 species, herbarium specimens of 96, and 35 cases of living rootstocks and bulbs. He was sent out again to make a further haul in 1905, this being followed by yet more expeditions returning in 1907 and 1910. It was these expeditions that indicated a tantalizing flora in the west of the country, a challenge to George Forrest (1873-1932) who made 7 trips between 1907 and 1932 sending back large numbers of seed, notably from Yunnan. His efforts were supplemented by those of Reginald Farrer (1880-1920) in Kansu and William Purdom although interrupted by the first world war. The remarkable opportunities also attracted well-known collectors Meyer, Kingdon Ward, Rock and others.

Hybrids

The period from 1930 is marked by major developments in science and technology as the the horticulturally unexplored regions of the globe dwindled. The world had entered a new era of genetics and microbiology on the way to genetic engineering and the exploration of man-made (anthropogenic) novelty.

Weeds

Weeds are plants growing where they are not wanted, whether that be in the wild, in commercial crops, gardens, or elsewhere. Weeds, as defined here, are, in broad terms, plants ultimately originating from cultivation by accidental or intentional human agency – they are, so for our purposes they are part of global cultivated plant geography. They are an odd category of plants that have, literally, escaped from the formal (intended) process of cultivated plant transfer. Those plants that have escaped from cultivation to reproduce successfully in the wild are referred to as being ‘naturalised’.

Our interest in naturalized plants concerns their origin and disperal, the economic and environmental impact and management. Their management requires that we understand their origins and biology.

A first step is to develop estimates of their proportions in relation to the other major plant groups. Australia will serve as an example.

Plant naturalization in Australia

So the advent of neophytes (defined by Pysek (2003) as species introduced after the year 1500 is a direct consequence of European settlement in the late 18th century and plant globalization resulting from a subsequent increase of global trade in goods and people. Though records of naturalized plants can be found in Floras (the first Australian census by Mueller in 1882) it was not until Randall (2007) that an inventory of alien species was compiled. Interest has focused on the alien flora’s change over time, taxonomic composition, weed status, purpose of introduction, and success of introduction . However, no clear indication has been given of the introduction pathways and their relative risk. Dodd et al performed such an analysis using data available from the Australian Virtual Herbarium (CHAH 2014) seeking to determine patterns of naturalization and their change over time and the risk posed by plant introduction using distributions that indicated plants growing outside their natural range. These were compared with best estimates of introduction purposes using the World Economic Plants database (USDA 2014 – Animal fodder, animal forage, environmental erosion, ornamental, soil improver, food additive, human food, materials esp. wood)) according to economic categories in the Economic Botany Data Collection Standard (Cook 1995).

Of the over three million records 2699 species in 1061 genera and 161 families were located – 74% dicots, 24% monocots, 1% gymnosperms, and 1% pteridophytes. This gave a naturalized species density of 392 sp./log (km2) and assuming 20,376 native species this made up 12% of the total flora. The families Poaceae, Leguminosae, and Asteraceae made up 33% of the total. The rate of naturalization was uniform, increasing linearly at the rate of about 20 species per year over the period 1880-2000. There was also a uniform rate for genera and families – about seven genera and one family per year. Geographic source of species was about 47% Europe, 30% Americas, 14% Africa, 6% Asia, 2% Oceania with the number of possible source countries increasing over time and the taxonomic diversity increase over time at least partially due to changing pathways of introduction. Western and northern Europe dominate the species geographic distributions, especially those naturalized prior to 1900. Countries with Mediterranean and temperate climates were also requent sources. Of the economic categories, ornamental horticulture made up 66% of the species with animal and human foods more likely in the late 1800s to early 1900s then declining. Those naturalized plants considered weedy were greatest in the period 1890-1920.

By infering the purpose of plant introduction and its likely source it was posible to identify high-risk pathways of introduction. Ornamental plants originated most frequently in the United States. Changes over time indicated a declining influence of Europe with the possible exception of Spain. Using this data set it was possible to infer that between 1860 and 1890 a naturalized species was most likely to be in the Leguminosae or Poaceae used for animal food and sourced from Italy or France. Between 1920 and 1950 it was most likely to be Poaceae used for animal food and sourced from France or the United States. From 1980-2010 it would have been an ornamental in Iridaceae or Ericaceae from South Africa.
Overall there was a transition from food species originating in Europe, through food species and ornamentals originating in North America, to ornamental and accidental species originating in South Africa (also the Americas and Asia) correlating with the socio-economic development of Australia.

Plant commentary & sustainability analysis

The future

Plants will always be an integral part of the human diet and so agriculture will be a part of human life and economic botany for many years to come. However, the phase of discovery and redistribution appears to be largely behind us. The countries of the world are now closely interconnected and interdependent. Like the colonialism before it, globalization has provided material well-being for many but also generated a less fortunate underclass. But the price has been a uniformity of lifestyle and diminishing mystery of the exotic as we join the global village. It is possible that there may still be miracle medicines, new foods, and exquisite ornamental plants to be discovered in the Amazon jungle, Asian rainforests, and other remote regions of the world – but this possibility is diminishing fast.

With the benefit of hindsight, we can judge the past as a time of impulsive greed and intrepid adventurers with a winner-take-all philosophy. Though human nature may not change, the nature of the world is now completely different. Though the past may be perceived negatively, we now have an opportunity to pause, reflect on what has happened, and plan for a more equitable and sustainable future.

The most marked ways in which humans have impacted on plants are through changes to their biology, geography, and modes of cultivation.

Though some changes in modes of cultivation may occur in the future the basic pattern and composition of plants devoted to the major modes of cultivation – agriculture, horticultural crops, forestry, and ornamental horticulture – seem unlikely to change dramatically as the phase of international exchange and re-distribution of food plants has now passed. It is likely that for some time the logging of world rainforests will continue for some time in regions where human need overrides environmental concerns, but if human needs can be met then perhaps reafforestation will occur in tropical and subtropical regions as has occurred in the northern hemisphere.

Much of the plant future will probably be marked by the influence of advanced scientific techniques. Humans have altered the biological make-up of many of their cultivated plants such that the cultivated landscapes we drive through now consist of anthropogenic plants or cultigens. This process of biological change began with the (probably unconscious) process of plant selection that was part of the Neolithic Agricultural Revolution but it gathered momentum in the 20th century with the application of genetics to deliberate plant breeding. Today biological manipulation has taken a further step into genetic engineering (from the 1980s) which has generated its own suite of problems: concerns about their effect on health, labelling in shops, the moral and other uncertainties related to genetic tampering such as the consequence then why do we es of genetic pollution (the spread of ‘man-made’ genes into natural populations), problems concerning the ethics of intellectual property and royalties, genetic piracy, creation of frivolous genetic monsters, and so on. This deluge of misgivings is countered by the possibility of crops that have the potential for far greater yields, disease-resistance, and the relief of global poverty.

We need to monitor the geographic and temporal history of plant globalization, its costs and benefits, including the risks associated with different plant and trade route pathways.^[11] This process is only just beginning (see Dodd for Australia, and SESYNC for America where over 2.5 billion plants were imported into the United States in 2009, for a brief outline of import-export restrictions in Britain and the EU see RHS^[12]).

We use cultivated plants to nurture both the body (as food, medicine, and materials) and the soul (through their spiritual, intellectual, and ornamental values). To derive maximum benefit from them, we have moved them around the world using the most efficient transport systems available at any particular time and place. We have also changed them physically, by using the most effective scientific means at our disposal – passing historically from selection (from around 12,000 BCE), breeding combined with selection (well established by 1930s), and genetic engineering (1980s onwards). In this sense, most horticultural crops and the plants of agriculture and forestry are anthropogenic, less so those of ornamental horticulture.

The human domestication of crops from wild plants has been well studied although in many cases the selection process has taken so long that wild ancestors are unknown. The distribution of ornamental plants is more complex and yet to be given appropriate attention.

Since the Bronze Age human plant use has been most evident outside city walls in the mass-production of food, the total space that has been dedicated to food increasing as the human population has increased from about 10 million in 10,000 BCE, to 350 million in 1500 CE, and 7.5 billion today. wild nature has been progressively tamed into cultural landscape.

The human dispersal of plants gathered momentum when agrarian communities turned into urban city-states that engaged in long-distance exploration, expansion, and trade. Bronze Age civilizations of the East and West exchanged luxury and other goods along the Silk Road, this route being most active during the period of the Roman Empire and Han Dynasty before the strategic, economic, and scientific expansion of Europe in the Age of Discovery. Western maritime trade moved out of the Mediterranean to establish an Atlantic economy while other trade routes reached across the Indian Ocean to the Pacific Ocean and Indonesian Archipelago during an Enlightenment flurry of scientific inventory and economic growth. Through the 17th to 19th centuries uncompromising colonial expansion knitted disparate trading networks into a European-led global economy. Two key drivers at this time were the Dutch and British East India Companies which, it can be claimed, together founded modern capitalism. They not only raised vast revenues for their countries but influenced diet, fashions, and language, the British East India Company ensuring London would become the greatest city in the world and eventually its financial hub. India had proved pivotal in establishing early trade networks with a cloth centre established in Madras in 1639 (Bombay and Calcutta were added later), protected by a fort (Fort St George), and linked to East Indian trade. By 1700 there was a vibrant trade in gingham, calico, chintz, tea, and coffee. From these times came the Indian words dungarees, pyjamas, and bandana. Eventually Benghal was ruled by this private company, which was only taken over by the British government when difficulties arose.

This Western ascendancy, the Great Divergence, was injected with additional impetus as the Industrial Revolution in north-west Europe released the additional power of machinery using fossil fuels, modernizing transport and communication systems and creating industrial agriculture.

The most obvious presence of cultivated plants in our world, both spatially and in terms of biomass, has occurred through the use of land for food production. The Great Divergence bequeathed us a planet with about 11% of the land surface used for crops (UNFAO, 2015) although this figure can conceal much more extensive human influence. In Australia, for example, when grazing and rangeland is added to that of dryland and irrigated agriculture the total land surface influenced by human activity (including modification of natural plant communities) is closer to 60%. Human appropriation of net primary production totals about 25% (Kraussmann et al., 2013). Cultivated plants are thus a good indicator of human impact on the planet in today’s geological epoch, the Anthropocene.

The same is true for forestry. Though only about 5% of forests (which cover about 30% of the world’s land surface) are comprised of timber plantations a far greater percentage is actively managed, enclosed, or semi-natural.

We have given a superficial outline of the way plants useful to humans have gradually been drawn into a global economy; but how does cultivated plant globalization impact on the world?

Apart from the agricultural cereals of the Neolithic Revolution it appears that the first major influx of exotic plants to Britain occurred during its occupation by Roman garrisons (c. 45-410 CE). Archaeological research has revealed that during this period about 50 new food plants (mostly Mediterranean fruits, herbs, spices, and vegetables) were introduced by the Romans to supplement the local food (Van der Veen & Hill, 2008). Of these 50 species, 36 (over 70%) are now naturalised in Australia – a striking example of the cultural diffusion of plants across the planet, and a demonstration of how plants do not recognize the boundaries of our fields and gardens.

There are now near-cosmopolitan tropical and temperate urban weed floras. Weedy plants growing around the rails of Kew’s tube station Richmond, Surrey, are almost identical to those growing at Richmond Station, near the Royal Botanic Gardens in Melbourne, Australia – another stark reminder of the process of globalization and plant homogenization.

Today we confront the blurring of distinctions between natural landscapes and cultural landscapes. What is natural and what has been genetically altered? What is wild and what is cultivated? Already the management of alien and invasive species is now a major global expense, what will be the consequences if plants continue to escape from gardens and agriculture to mix and interbreed with native plant communities?

Today most of the world’s population lives in cities. We are not only divorced from wild nature but also from the cultivated plants of our rural surroundings, not knowing whether the vegetables and fruits we buy in supermarkets were grown nearby or in another country. The tomato we associate so closely with Italian cuisine is native to South America, chilli peppers of South America are widely grown in India, Australia’s only native commercial crop, the macadamia was, until recently, mostly sourced from Hawaii, the oil palm grown so widely in Indonesia and Malaysia is native to West Africa.

The urban areas of the world take up less than 0.5% of its land surface. The spatially widespread but few species used in the monocultures of agriculture and forestry contrast with the numerous ornamental species that are largely confined to urban parks and gardens. Garden plants are also, for both better and worse, globalized. As we have seen, we owe much of this to the English who remain the world’s greatest gardeners: ‘Other countries have quickly acquired (doubtless with the help of the RHS Plant Finder) the same plants we grow here, resulting in the internationalisation of the world’s garden flora.’ (Lord, 2017).

Just as uniting the world in trade has given us food choice, so the ‘internationalisation’ of garden treasures has given us an almost infinite plant palette for our cities, streets, parks, and gardens.

Since we benefit locally from global factors then we must think globally to minimize any negative impacts our horticultural diversions might have on the planet. The future is about sustainability – the cooperative integration of the world’s peoples to achieve an equitable distribution of the world’s limited resources with minimal social disruption and environmental impact. So how can we all help?

A global inventory of wild plants is now underway as a world flora. We need parallel inventories of cultivated plants including records and dates of plant introduction, commercial availability and use, also more detail on the historical factors that drove this process together with their environmental, social and economic impacts. In short, we need an ecological awareness of the role that ornamental plants are playing in global environmental history.

The fusion of plants with human affairs has made the interpretation of plant history as controversial, ambivalent, and complex as the interpretation of human history itself. Bound to the fortunes of civilizations and empires they have generated both misery and wealth but with the greatest impact through the period of European colonial expansion beginning in the 15th century and culminating in the economic botany of imperial Britain during the 18th and 19th centuries. The material comforts following the wealth generated by plant products existed alongside the horror of the slavery that produced them. Temperate European agriculture bequeathed pastoral landscapes and a culture of gardening to the colonial neo-Europes that, together with their mother-countries, would subsequently dominate the world.

What we can say for sure is that the human cultivation, biological modification, and redistribution of former wild plants has changed for all time the appearance and ecology of planet Earth, contributing to the most recent geological epoch we now know as the Anthropocene.

Key points

The commodification and globalization of plants has accurred in two major phases. The first phase the dispersal pf plants out of centres of civilization on Mesopotamia, China, and Meso-America as an integral part of the Neolithic Revolution. The second phase occurred during the expansion of European exploration and commerce that occurred mostly during the Ages of Discovery, Enlightenment, and the 19th century British Empire. The attraction of sugar was centred on the Caribbean while spices, textiles and tea drew merchants into Asia.

European settlement entailed vast European land grabs in North and South America, Africa, Australia, New Zealand, Tasmania and elsewhere, a proliferation of ornamental plant nurseries, intensive collection of plant diversity (both living and dried), a surge in botanical and horticultural exploration, a renewed interest in economic botany with Kew at its hub, the development of the English landscape garden.

The Incense Route transport frankincense and myrrh from the southern Arabian Peninsula in today’s modern Yemen and Oman to the Mediterranean ports using the camel (domesticated around 1000 BCE) taking 62 days to complete according to the account of Roman historian Pliny the Elder.

Amber trade flourished under the Romans then, during the Crusades of the 12-13th centuries it was taken over by the Teutonic Knights. Remnants of the old AAmber road, known as ‘The Amber Highway’ still remain in Poland.

A 9500 km long tea route passing from the tea-producing Chinese Hengduan Mountains through Tibet to India dates back to about 1600 BCE. It was also used to trade Tibetan warhorses. But gathering use from about the seventh century CE with large-scale trade beginning with the Song dynasty (960–1279) diminishing in importance as maritime trade routes developed.

A Roman salt road (Via Salaria) ran from the Roman port of Ostia across Italy to the Adriatic coast and another across Germany.
Trans-Saharan Trade Routes
Ran from North Africa to West Africa across the vSahara desert. Arising around the fourth century CE, by the year 1000 huge camel caravans carried gold, slaves, salt, cloth and other commodities. It helped spread Islam from the Berbers in North Africa into West Africa. In the 16th century, as Europeans annexed this Trans-Saharan trade to European-controlled trans-Atlantic trade moving trade from inland to coastal ports.

TIN ROUTE
From the Bronze to Iron Ages the comparatively rare tin was alloyed with copper to make tough bronze (arising in the Near East c. 2800 BCE). Tin routes in the first millennium BCE between mines in Cornwall to France, and then down to Greece and beyond. Hillforts have yielded artifacts like coral and gold in a route that connected northern Europe to the Mediterranean.

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First published on the internet – 1 March 2019