William Bertram Turill & Alpha-Omega Taxonomy

Sanjeet Kumar
sanjeet.biotech@gmail.com
Department of Botany
Ravenshaw University, Cuttack

William Bertram Turrill was an English botanist. He was born in Woodstock. He worked in the Royal Botanic Gardens at Kew and was responsible for many innovations including a mathematical classification of leaf shapes. He received the Order of the British Empire in 1955 and the gold medal of the Linnean Society in 1958, He was elected a Fellow of the Royal Society in 1958. This botanist is denoted by the author abbreviation Turrill when citing a botanical name. He did a approach regarding the stages of taxonomic study as Omega taxonomy. Our level of knowledge about plants use to varies, of course, in different ways. For instance we know far more about the vascular plants than about the lower green plants; about plants of the North Temperate regions than about those of the Tropics; and about plants of great economic value than about those of little commercial interest. According to Valentine and Lave, there are three stages of floristic study:

1.      The evolutionary phase: Involving collection and subsequent classification from a limited range of herbarium specimens.

2.      The systematic phase: Extensive herbarium and field study of a wide selection of material of each taxon are carried out.

3.      Biosystematic phase:  Detailed genetical and cytological studies.

Davis and Heywood rightly added a fourth stage:

4.      The Encyclopedic phase: Data forms a very wide renge of disciplines are assembled to form a good predictive type of classification.

Earlier, Turrill had expressed the same idea differently and perhaps more usefully, because his notion emphasized the continuousness of these phases. Turrill spoke of an Alpha taxonomy, equivalent to the first and second of the above form phases, based solely upon more or less external morphological characters.  The term “Alpha” refers to alpha taxonomy being the first and most basic step in Taxonomy. He also proposed Omega taxonomy which is based upon all available characters. Turrill, while commenting upon our attempts in this direction said “some of us please ourselves by thinking we are now grouping in “Beta” taxonomy. In 1963, Davis and Heywood were more certain.  The concept of alpha omega taxonomy ties in well with the view put forward at the start of present study where alpha taxonomy forms the basis of biology while the final accumulation of all data is ultimately incorporated into omega taxonomy. In botany, an alpha taxonomist who names taxa is called an Auctor . Names of certain authorities are sometimes abbreviated. It was quite common during the early years of Linnaean Taxonomy. It is no longer done in zoology but a system of abbreviations is still used in botany. Many of the more well known species of plants were described by Carl Linnaeus in Species Plantarum, published in 1753, and this is considered the formal starting for the botanical code. Thus the common buttercup is Ranunculus acris L., where the “L” is the standardized abbreviation for Linnaeus.

For a long time the term “taxonomy” was used for what is today seen as alpha taxonomy. Over time, the term “taxonomy” has gained several other meanings and has thus become potentially confusing. To some extent it is being replaced, in its original meaning by “alpha taxonomy”. As such, alpha taxonomy deals mostly with actual organisms, fossils species and lower ranking taxa. Higher ranking taxa including clades and grades mostly are the province of  “beta taxonomy” more commonly called systematic. Systematics as a science deals with the relationships between taxa, especially at the higher levels. These days systematic is greatly influenced by data derived from DNA from nuclei, mitochondria and chloroplast. This is sometimes known as molecular systematic which is becoming increasingly more common, perhaps at the expense of traditional morphological taxonomy.