484 RypDBERG: NOTES ON ROSACEAE 
standing in the same relationship to D. Drummondii as D. octo- 
petala argentea Blytt stands to D. octopeiala. This species has also 
been collected in the Canadian Rockies, Macoun 65125. 
GEUM 
Geum vernum (Raf.) T. & G. was originally described as 
Stylopus vernus Raf., and the writer is somewhat in doubt if this 
species should not be regarded as the type of a distinct genus. 
The habit is that of a typical Gewm, but the receptacle in fruit 
becomes stalked above the hypanthium, and the bractlets are 
usually lacking. Occasionally, however, there are found minute 
bractlets in this species, and the receptacle is more or less stalked 
in Geum rivale. The generic characters of Stylopus do therefore 
break down, and it is perhaps better to regard it a Geum, especially 
as the general habit is not essentially different. 
Geum virginianum L. This species has in general. been very 
well understood. Murray, however, applied that name to G. 
canadense and redescribed the true G. virginianum as G. laciniatum 
Murr. Many have referred the latter synonym to G. canadense 
and Scheutz suggests that it may be the same as G. agrimonioides 
C. A. Mey.,i.e. G. Meyerianum Rydb., but in my opinion it belongs 
to G. virginianum L. 
Geum camporum Rydb. Some twenty years ago, the writer, 
when working over the Rosaceae of Nebraska, had trouble in 
‘determining some specimens of Geum, and did not know whether 
to refer them to G. canadense or to G. virginianum. These speci- 
mens had the thick leaves, the stout stem and branches, and the 
large fruiting head of the latter, but the receptacle was not glabrous 
and the achenes had the pubescence of G. canadense. When 
working up the material for the North American Flora, he found that 
the plant was more common in the prairie region of the Mississippi 
valley than was expected and that its range extended from Minne- 
sota and South Dakota to Arkansas and Texas. As both G. virgint- 
anum and G. canadense are found in the region, G. camporum might 
be regarded as a hybrid of the two. These two have about the 
same distribution (except that G. virginianum is not found in 
Mexico), but G. camporum is not found except in the western part 
of their common range. _ It is, therefore, not probable that it is a 
