Wednesday, 26 February 2014

The naming of plants

Plant taxonomy is a system of classification used by botanists and horticulturists.  A taxonomist is a namer of plants.  He looks into the characteristics, the kinship with other plants and to what family it belongs. Sometimes the differences are minute.

In our western world the very first descriptions of plants were made by the Greek philosopher, Theophrastes, 300 BC.  Theophrastes was born on the island of Lesbos, came to study under Plato at the Academy in Athens.  At the Academy he met Aristotle, who himself was a student of Plato.  Aristotle set up the Peripatetic School at the Lyceum in Athens.  The name ‘Peripatetic’ referred  to the colonnades of the Lyceum under which the students met. 

Theophrastes was invited to join Aristotle and whereas Aristotle was deeply engrossed in finding out the history of animals, Theophrastus started a similar enquiry into plants.  He is considered to be the ‘Father of Botany’.  In his ‘Historia Plantarium’ Theophrastus divided the plants into 3 categories, trees, shrubs and herbs and separated them into annuals, biennials and perennials.  He did not appreciate how imported flowers were to plants.  He did know that if you shook the male flowers over the female flowers, it resulted in fruit, but did not understand the significance of pollen.  In total he described 500 plants. 

One has to remember that the interest in plants was mainly from a medical point of view.  Plants were the only way to treat sick people and till the 15th century the interest in plants were restricted to plants that were of medicinal value.
People followed religiously the teachings of Theophrastus (300 BC), Dioscorides (40-90 AD) and Pliny (23-79 AD).  After all everyone knew that the Greeks and Romans were the source of all knowledge.  Dioscorides’ Materia Medica’ was the core of European pharmacopeia through to the 19th century.

At the time it was not unusual for someone who had an interest in plants to know the names of all the plants he came across, certainly all those that were in general use in Europe.

When printing became available in the early 1400s the first botanical books that were printed were herbals.  Some had beautiful illustrations, others were not very accurate, just an artist imagination of what he thought the plant looked like.

As long as Europe stayed isolated there was no need for any systematic means of grouping or identifying plants; all one needed was a good memory.

This all changed.  Between mid 15th and mid 16th Century,  20 x as many plants entered Europe from the East, then the  previous 2000 years. 

The fall of Constantinople in 1453 to the Ottoman Empire (it had previously been held by the eastern branch of the Holy Roman Empire), brought about changes. 

Europeans who visited Constantinople were introduced to plants never seen before.  They were bulbs:  tulips, fritillaries, irises, crocuses, alliums, hyacinths, anemones and as such easy to transport.

Constantinople was the end of the line on the silk route from China passing through the Tien Shan mountains, where most of the bulbs came from.  The journey led from China through Tashkent – Samarkand – Bukhara – Turkmenistan – Baku - Jerevan to Constantinopel. 

These bulbs needed names, the local names from where they originated were lost or corrupted along the way. They had to have names if only for practical reasons.

The capture of Constantinople made everything originating in China and India more expensive for Europeans, as the silk route was now under the control of the Ottomans.

Something had to be done.  Columbus set out in 1492 in a westerly direction believing he could reach Asia this way.  He mistakenly thought he had landed in India, hence calling the native population Indians, but unknown to him he had arrived in the New World.

He brought back with him:  corn, pineapples, squash, sunflowers, tomatoes, new varieties of beans, tobacco, sugar and cacao, but no spices, which was one of the reason for sending him on this journey.

The Spanish physician, Nicolas Monardes (1493-1588), was the first person to publish books that introduced New World plants.  He mentions the Aztecs drinking chocolate flavoured with vanilla and chillies.

The Portuguese were very interested in finding a route to the Orient.  The first Portuguese ship to sail past the equator was in 1471.  Fifteen years later Bartholomew Diaz became the first European to round the Cape of Good Hope, but did not get much further as his crew threatened mutiny if he continued.

In 1492 Vasco da Gama rounded the Cape of Good Hope and landed in India.

All these expeditions brought back plants with them.  There was a desperate need to name all these plants as it became harder and harder to keep track.  Some sort of system had to be found.

At the time the only means of identifying plants was by observation and noting the significant specifics of each plant.  The first microscope was not invented till 1595.

The first botanical garden was founded in 1548 in Pisa (still existing today) and the second one in 1545 in Padua.  Around this time the first herbarium appeared.

More people were learning to read and write not just priests and merchants. It became more acceptable for intellectuals to deepen themselves into the natural world rather than religious doctrine.

Some botanists explored different ways of classifying plants like the Italian, Andrea Cesalpino (1525 -1603) and the Swiss, Jean Bauhin (1525-1603), but their suggestions did not find a following.

In 1730, a Brit, John Ray published ‘Methodus plantarum’ (Plant Systematics) in which he classified nearly 18.000 species according to their shape and appearance. 

At the same period Nehemiah Grew made a leap forward with the startling suggestion that the stamens of a flower were in fact the male sexual organs.  Before it was thought they were the breathing organs of the plant.

The Swede, Carl Linnaeus (1707-1778), is sometimes called the father of ‘Modern Botany’.  He applied a binomial naming (two-name) system, giving the plant:

a Latin first name, written in italics, the first letter of the name in Capitals.
a Latin surname, written in italics and in small letters.

Latin being the language used universally in the educated world.

A two part explanatory system already existed, but it was very cumbersome.

For instance, a plant was named ‘Plantago ‘, this was then followed by ‘a plantain with ovate lanceolate leaves becoming softly hairy, a cylindrical head and a smooth stem’.  All this in Latin of course.

In Linnaeus’ system it became ‘Plantago media’, in English ’Hoary Plaintain’.  Much easier to remember.

Linnaes standardized the naming of nearly 6000 different plants by using a two-name (bi-nominal) system.  The plants he standardized are followed by a capital L.  i.e. Quercus robur L.

Since Linnaeus’ days much progress has been made in the understanding of plants:
1.     better microscopes
2.     awareness of the biological significance of the stamens and pistils in a plant.
3.     Better understanding of floral shape and appearance.
4.     The DNA of a plant.

In addition to the bi-nominal system, plants were organised according to botanical similarities into broad groups called families.  A large group of plants sharing certain broadly similar structures:
For instance the family Labiatae – Mint family.

These families are divided again into a genus (plural genera).  Plants that have similar characteristics,
For instance the genus ‘Lavandula’.

These genera are divided into species. Closely related, but distinctly different plants belonging to the same genus:
For instance:  Lavandula angustifolia, Lavandula latifolia, Lavandula stoechas.

Further to the above there are subdivisions:

Subspecies and varieties = minor often geographical variations in species in the wild.  These are shown by a third Latin name: 
For instance:  Rosa foetida bicolor.

Cultivars – plant variants found in cultivation.  Cultivars occur naturally or by selection.  First comes the Latin species name, followed by a 3rd name, not in Latin.
For instance:  Lavandula angustifolia ‘Hidcote’.

Hybrid – a cross between 2 species.  This is sometimes shown by an x between the genus and species name.
For instance:  Lavandula x intermedia.

Proper names are sometimes changed. Name changes occur when the plant was put into the wrong genus to start with, or the plant is given back its earlier name which has gone missing and is found back. Some plants have Greek names rather than Latin ones, referring to their long history.  For instance: Narcissus and Dianthus.  A lot of names ending in ‘us’ are of Greek origin.

Most wild plants have only two names. 

From the 16th century onwards, gardens were being created. Not just for medicinal purposes but from an aesthetic point of view.  Initially it was just for royalty and noblemen.

Over the next 200 years explorers were sent across the globe to collect plants.

One of the first was John Tradescant jr, (1606-1662).  He explored the New World and returned with plenty.  One genus brought back by him and named after him is Tradescantia (Spiderwort), Tradescantia fluminensis (Travelling Jew).

Joseph Banks (1743-1820) explored Labrador, Newfoundland and the South Pacific.  He helped to found the Royal Botanic Gardens at Kew, and the Royal Horticultural Society, bringing seeds and plants from all over the world.

Joseph Dalton Hooker (1871-1911), director of Kew Gardens, established it as a top centre for scientific research on plants.

Robert Fortune (1812-1880) travelled to China.  Brought back just to mention a few:  Dicentra spectabilis (Bleeding Heart);

Platycodon grandiflorus (Balloon flower); Pompom Chrysanthemums; Anemone hupehensis (Chinese Anemone); Lonicera fragrantisima (Honeysuckle) and many more.  He was one of the first to ship live plants back successfully using a mini travelling glass greenhouse, called a ‘Wardian Case’ named after their inventor Dr. Nathaniel Ward.

Ernest Henry ‘Chinese’ Wilson (1879-1930) brought back roses; primroses; lilies; azaleas.  He discovered 3.356 species and varieties, 900 which were not previously known.

In 1930, taxonomists finally agreed on a single International Code of Botanical Nomenclature.  This code is revised every 6 years.  The revisions are published in ‘Taxon’, the journal of the International Society of Plant Taxonomists, then voted on at a meeting that is held immediately prior to an International Botanical Congress.


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