162 Transactions. 



(8.) Each microspecies of the combination forming an aggregate species 



should theoretically receive a varietal name. 

 (9.) But in practice the procedure advocated in (8) would defeat its 

 purpose if the microspecies were too much alike, so in this case 

 groups of virtually identical microspecies can receive varietal 

 rank. 

 (10.) It follows then that, similarly with species, varieties are of two 



kinds, one reproducing itself true and the other an aggregate. 

 (11.) Aggregate varieties, though abstractions only, so far as the eye goes 



approximate to true entities. 

 (12.) The description of an aggregate species applies to no special indi- 

 vidual, but includes the striking characters common to all its 

 varieties; obviously, then, there is no "type." 

 1 13.) If the opinions as given above are accepted, a trinomial nomen- 

 clature becomes necessary, the first name being that of the genus, 

 the second that of the species, and the third that of the variety. 

 (14.) If the opinion is held that every microspecies has been at one time 

 related closely to other microspecies, it follows that even the in- 

 variable species mentioned in (3) should be given varietal names. 

 But this procedure seems unnecessary, and perhaps mischievous, 

 since a binomial for such species is convenient and it indicates 

 that the specific group stands apart from all others.* 

 (15.) In certain cases groups, otherwise well defined, seem to be united 

 by " intermediates " which cannot be joined to such groups or 

 made into one or more species. Such " intermediates," according 

 to the teachings of genetics, may be assumed to be hybrids be- 

 tween microspecies, and their occurrence should not forbid the 

 separation into species or varieties, as the case may be, of the 

 distinct true-breeding groups (microspecies) which are connected 

 by such presumably hybrid intermediates. f 

 As a botanical ecologist, endeavouring to define and classify the plant- 

 communities of New Zealand and to learn something about the physiological 

 requirements of the species and the physiology of form, I have keenly felt, 

 for many years, the want of names for many well-marked groups of indi- 

 viduals which, though fitting fairly well into one or other of the recognized 

 aggregate species, differ so greatly in their ecological requirements from 

 other members of the species to which they are referred that to call them 

 by the same name is most misleading, and in no few instances will cause 

 incorrect ecological deductions.t 



* Of course, as at present accepted, there are many different degrees of specific 

 isolation, but it should be possible to gradually bring about greater uniformity in this 

 regard. 



f This has frequently been done in the New Zealand flora, but not because of any 

 special biological explanation such as that of microspecific hybrids. Celmisia discolor 

 and C. incana (Manual, pp. 304-5), Gna/phalium Lyallii and G. trinerve (Manual, p. 323), 

 and many species of Veronica are cases in point. On the other hand, distinct micro- 

 species are denied specific rank owing to their being connected by " intermediates." 

 Examples are : Epilobium pedunculare reduced to a var. of E. nummular if oliuiii (Manual. 

 p. 180), the treatment of the groups included under Huheria populnea (Manual, p. 7!l). 

 and the retention of vars. robusta, minor, and lanata as varieties of Craspedia uniflora 

 (Manual, p. 348). 



J Of what value would be an account of the leaf-anatomy or the rate of transpiration 

 in the leaves of certain individuals of Pittosporum tenuifolium, Acaena Sanguisorbae, 

 Aristolelia fruticosa, Geranium sessiliflorum, Celmisia coriacea, and Myosotis antarcfica 

 under the above specific names, unless a description of the actual plants dealt with were 

 given — i.e., unless they were accorded for the time being the status of microspecies ? 



