303 
"P. nivea dissecta Wats. Proc. Am. Acad. 8: 559. 1873. Not 
P. dissecta Pursh, 1814. : 
Leaves quinate as well as ternate; leaflets deeply toothed, in 
the quinate leaves the lower ones often smallef. 
POTENTILLA NIVEA UNIFLORA (Ledeb.). 
Potentilla unifiora Ledeb. Mem. Acad. St. Petersb. 5: 543. 
P. nwea Vahliana American authors, at least in part. 
The true position of this plant is difficult to determine. It 
may be placed as a variety of P. nivea or of P. Vahliana or as a 
Species intermediate between the two. Ledebour made it a 
variety of P. villosa, which it somewhat resembles as to the leaves. 
It has the caespitose habit, short nearly leafless stems, and short 
wedge-shaped leaves of P. Vahliana. Its flowers are nearly of the 
same size as those of that species, but the petals are obcordate, 
not reniform, and the sepals and bracts are those or P. nivea, de- 
pauperate forms of which grade into it. It is found in the arctic 
regions from Greenland to Alaska and adjacent Asia, but also in 
the Rocky Mountains of Colorado. Apparently all specimens 
labelled P. nivea Vahliana from the Rockies belong to P. mivea 
uniflora. It was evidently this form that Watson had in mind 
when he made the statement that P. Vahliana was a depauperate 
few-flowered form of P. nivea. 
POTENTILLA VAHLIANA Lehm. Monog. 172. 1820. 
P. hirsuta Vahl; Hornem. Fl. Dan. f/. 1390. Not Michx. 
This is very low and matted, the large flowers a little exceed- 
ing the leaves. The petals are very broadly subreniform, 7. ¢., 
broader than long, and therefore overlap each other ; the bractlets 
are broadly oval, obtuse and about equal the ovate sepals. The 
whole plant is covered with yellowish villous hairs besides the 
tomentum. Lehmann was in some doubt whether he should regard 
it as a variety of P. nivea or asa distinct species. He made it a spe- 
cies on the authority of Vahl, who knew the plant in its native 
haunts. Seeing only P. nivea and P. Vahliana nobody would hesi- 
tate in assigning specific rank to the latter. The trouble comes 
in when one is to draw the line between either and P. uniflora. : 
Lehmann states that ?. Vahliana was collected by Richardson in’ = 
