66 Transactions. 



Art. VI. — A Consideration of the Terms "Species" and " Variety" as used 

 in Botany, with Special Reference to the Flora of New Zealand. 



By L. Cockayne, Ph.D., F.L.S., F.R.S., Hutton and Hector Memorial 



Medallist. 



[Read before the Wellington Philosophical Society, 22nd September, 1915 ; received by 

 Editors, 30th December, 1916; issued separately, 6th July, 1917.] 



Lack of Uniformity in the Taxonomic Employment of the Term 



" Species." 



Notwithstanding the great progress made in botanical science during the 

 last century, the present-day taxonomic conception of the terms " species " 

 and " variety " is a heritage from the past which has been handed down 

 with but little change from the time of Linnaeus. In other words, although 

 Darwin revolutionized biological thought with his doctrine of organic evolu- 

 tion, taxonomic thought and procedure is even yet dominated by the dogma 

 of special creation. Darwin prophesied that " Systematists will be able to 

 pursue their labours as at present ; but they will not be haunted by the 

 shadowy doubt whether this or that form be a true species. . . . The 

 endless disputes whether or not some fifty species of British brambles are 

 good species will cease."* Unfortunately, the above prophecy is far from 

 being realized. In every land where " species-making " is in progress the 

 " lumpers " and the " splitters " are as hard at work as ever, but the latter 

 are now in the ascendancy, perhaps partly because the stock of so-called 

 " valid " species is rapidly declining, and partly because by many it is 

 considered a more laudable action to " create " a species than a variety; 

 but also there is being carried out a far greater amount of truly critical 

 work than formerly. 



That taxonomy should have proceeded on the old lines is really what 

 might have been expected, the doctrine of evolution notwithstanding ; for 

 the taxonomist is working with species as they are, and not with what they 

 may have been or are going to be. To all intents and purposes evolution 

 has created distinct species many of which are presumably just as invariable 

 as if they were the work of special creation ;f and the taxonomist is not 

 usually dealing with long rows of intergrading forms, but with fairly clear- 

 cut groups of individuals, which are occasionally connected by intermediates, 

 but for these latter are explanations available different from that of Darwin. 



If one possessing a fairly wide knowledge of the actual plants critically 

 examines the diagnoses of the species in almost any flora, it will stand out 

 clearly that such species (and, for that matter, their varieties) belong 

 to different biological categories — i.e., that there is more than one kind 

 of taxonomic species. Those forming an extremely common class do not 

 exist in nature as true-breeding entities : they may be considered ideas merely, 

 or at best quite artificial groups of polymorphic forms. The diagnosis of 

 such a species includes a number of distinct groups of individuals which, 



* Origin of Species, 6th ed., pp. 399-400, 1872. 



| Bateson strongly upholds the conception of specific distinctness, as opposed to the 

 belief of those who consider that species are " impermanent groups, the delimitations of 

 which are ultimately determined by environmental exigency or fitness " (see Problems of 

 Genetics, pp. 10, 11, and 12, 1913). 



