RypBERG: Nores ON ROSACEAE 379 
_ quarto of 716 pages and 20 plates, good paper and good large print. 
The descriptions in Latin are excellent and complete. To these 
are added elaborate discussions and notes in German. The 
synonymy is practically complete, and the citations have nothing 
of the vagueness so characteristic of many so-called monographs. 
As one should expect, a comparison of Dr. Wolf’s monograph 
and my treatment of the genus in the North American Flora 
discloses many differences; but most of these result from our dif- 
ferent views. Dr. Wolf is exceedingly conservative both as to 
genera and species, and the present writer has the reputation of 
being exceedingly “radical.” Dr. Wolf believes in large genera 
and broad species, and admits numerous varieties and forms; 
while the writer believes in small genera and narrowly limited 
species. If the diversity of two plant forms is of any value at 
all, the writer admits them as distinct species; if the variation is a 
trifling one, it is simply ignored. In this way the old rank of 
variety has been disposed of. Of course, also, many of the dif- 
ferences arise from the fact that Dr. Wolf had no or insufficient 
material of American plants and had to rely upon the printed 
descriptions alone in many cases. 
While Dr. Greene seems to go too far in splitting up the genus, 
Dr. Wolf is in my opinion too conservative. He has left Potentilla 
with about the same limitation as Lehmann had in 1856, only 
that he has merged even Duchesnea in Potentilla. I can not under- 
stand why he did not treat Sibbaldia in the same way. This 
genus is really much more related to Potentilla than Drymocallis 
and Dasiphora are. The only distinctions given by Dr. Wolf are: 
“Stamens 5 (very seldom 10); carpels 5-15 (the few Potentillas 
with only 5 stamens have always numerous carpels).’’ But there 
are several Potentillas that have few carpels although they have 
10-20 stamens. The distinctions are therefore not well drawn. 
Of course the position of the style, which I have used as a generi- 
cally distinctive character, will place it outside of Potentilla proper 
and in the group with Dasiphora. Dr. Wolf, however, does not 
regard this as a generic character and therefore, if consistent, he 
should have merged Sibbaldia into Potentilla. 
Dr. Wolf has divided the genus Potentilla into 2 sections and 
6 subsections. These subsections are based on the differentiation 
