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.
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:
Further to the above there are subdivisions:
Subspecies
Varieties
Cultivars
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.
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.