— 5 — 
another group where it retains the same rank, the first author shall be cited, 
and the author making the changes shall be cited, if at all, in parenthesis, 
not vice versa as ruled by the Vienna Congress in Art. 43. As examples 
and explanations under these various heads, with the help of recommenda- 
tions as e. g. that color should not be made the basis for specific or varietal 
names, and an appendix, in which he asserts among other things that the 
most of Warnstorf’s exotic species are questionably of specific value. Dr. 
Roll contrives to insert a good part of his present views upon Sphagnum. 
This circular as giving a relatively concise statement of Roll’s point of 
view in his controversy with Warnstorf may justify a word of explanation 
and perhaps of criticism. Our present knowledge of the anatomy of Sphag- 
num dates very largely from Schimper’s excellent monograph.^ To the 
facts therein set forth there have since been slight additions, notably 
Russow’s studies on the pores and other membrane-gaps of the empty leaf- 
cells. The anatomical details thus made available have formed the basis of 
subsequent systematic treatment, having been admirably used by Russow 
in his papers on the European forms, while Warnstorf aided and supple- 
mented Russow’s work on these forms and extended the same methods to a 
study of the exotic (/. e. non-European) species. Roll published in 1885 and 
1886 in Flora his sphagnological system for the European forms, ^ in which 
he had already adopted the views expressed in his present recommendations, 
viz.: that a species is a series of forms (z. e. is essentially a generic idea) and 
that a typical form of a species can not exist. It will be seen at once that 
the great divergence from the current conception of a species claimed for him- 
self by Dr. Roll is mostly an imaginary one, and that his “system” is an 
offence against the accepted principles of binomial nomenclature rather than 
the dawning of a great light. The obviously fallacious conclusion that 
Sphagnum is so different from all other genera of the vegetable kingdom , that 
it must needs have principles of nomenclature all its own rests upon a miscon- 
ception of the binomial system’s typical form! The botanist operating with 
a type-form does so as I understand the matter for the convenience and accur- 
acy of scientific nomenclature, and not necessarily with the idea imputed to 
him by Dr. Roll that all members of the species are exact duplicates of the 
“ typical form.” Dr, Roll’s system is simply not binomial, and it is for this 
reason that it has been -so difficult to give it a place in a system that is 
1. Published in .French. “Mem. p. s. a I’hist. nat. des Sphaignes”. Paris, 1857; in 
German with slight additions as “ Versuch einer Entwickelungsgeschichte der Torf- 
moose,” in 1858. 
2. “ Zur Systematik der Torfmoose.” 
