Cockayne. — The Terms "Species" and "Variety" in Botany. 75 



another such species, and not crosses between forms of the same aggregate 

 hardly distinguishable from one another. But undoubtedly this latter class 

 of hybrids — i.e., crosses between microspecies — forms a considerable percent- 

 age in many plant-populations, and in no few instances these hybrids con- 

 stitute connecting-links between groups otherwise distinct ; in fact, they 

 are then the so-called " intermediates." The surprising individual differ- 

 ences between the members of a young colony of Leptospermum scoparium 

 which I recently studied in the neighbourhood of Wellington can be best 

 explained on the above supposition, which doubtless holds good for many 

 aggregate species. If this be true, the presence of " intermediates " loses 

 much of its reputed taxonomic significance. In critical cases herbarium 

 studies are obviously futile ; no progress can be made by such means. 

 Experimental taxonomy, preceded by careful field observations, is alone of 

 moment, and should eventually decide all doubtful points. In this nothing 

 novel is suggested ; the procedure would be merely a return to the methods 

 so wisely advocated by de Candolle and Sprengel in 1821. 



The duty of the taxonomist is to arrange into groups the individuals 

 he is dealing with. This he can do by comparing large numbers of indi- 

 viduals and placing together such as appear to possess constant characters 

 in common. A number of such groups possessing definite characters 

 common to all, but each group having one or more characters peculiar to 

 itself, would form an aggregate species, the groups themselves being dealt 

 with as varieties ; or, where the aggregate species is extremely comprehen- 

 sive, some authors may first unite certain of these varietal groups, accord- 

 ing to their relationship, as " subspecies."* Such a plan as the above 

 is rarely followed. The species itself is first defined, perhaps from the 

 characters of a few individuals, or at times from one only. Later 

 on other individuals come into consideration, which, though probably 

 not exactly like those of the first defined group — they may, indeed, 

 be very different ■ — ■ appear closely allied, and they are referred to 

 the species, which accordingly is assumed to " vary." Should the new 

 groups be fairly distinct from the original set of individuals, they may 

 receive varietal names, and the species will be said to be " variable " ; 

 or if other more distinct groups are added as " varieties " it can be made 

 ''highly variable." or "protean," in which case the final word has been 

 spoken, and further research is considered unnecessary. f This conception of 



* The term " subspecies " has been but little used by writers dealing with the New 

 Zealand flora. Generally speaking, its use is confined to the primary subdivision of a 

 species of such magnitude that it becomes a moot point whether to treat it as a huge 

 aggregate or to split it up into smaller species. Where this latter course is not taken 

 the establishment of a "subspecies" is not infrequently in the nature of a compromise, 

 for the author, on the one hand, cannot make the aggregate of practical use in its 

 entirety, and, on the other hand, is averse to acknowledging that the divisions he 

 proposes are " good " species, so he adopts a group higher than a variety but rather 

 lower in rank than a species. This aspect of the question is well illustrated by Kirk's 

 treatment of Hoheria populnea in The Students'' Flora, pp. 71-72. Or an author, as 

 in the case of Bitter when dealing with Acaena Sanguisorbae, may establish subspecies 

 as convenient subdivisions, whose components, for practical purposes, are the varieties. 

 For the use of the syllable " sub " in taxonomic procedure, see Art. 12 of the Inter - 

 national Rules for Botanical Nomenclature. 



"j" The opposite course can be taken and a " highly variable " species can be made 

 to "vary" comparatively feebly. The treatment of Rubus australis Forst. f. in this 

 regard bv Kirk (Students' 1 Flora, pp. 125-26) and Cheeseman (Manual, p. 125) as 

 compared with that of Hooker in the Handbook, p. 54, is an instructive case, Hooker 

 defining the aggregate together with three varieties which he states " are united by 

 every intermediate form." 



