305 
POTENTILLA EMARGINATA Pursh, Fl. Am. Sept..%: 353. 3814, 
This species was described from specimens collected by Kohl- 
meister in Labrador. According to Lehmann(Hook. FI. Bor. Am. 
I: 194), P. nana, also, was collected by the same missionary. 
There is therefore a doubt which of the two. is the original P. 
emarginata. The latter, as understood by Vahl, Lehmann and 
others, is a stouter plant than P. zaua, has very narrow bracts, 
and leaves with acute teeth, of which the terminal is generally the 
largest. In both the flowering stems scarcely exceed the leaves. 
P. emarginata grows in Labrador, the Baffin Bay region, Green- 
land and Spitzbergen. 
POTENTILLA NANA Willd. Mag. Gesell. Naturf. Fr. Berl. 7: 
296. 1813. 
Dr. Watson states that this is a depauperate form of P. emar- 
Sata. * As understood by Lehmann, it is a plant much nearer re- 
lated to P. fragiformis, The habit is caespitose, as in P. emarginata, 
but the teeth of the leaves are rounded and the terminal one gen- 
erally smaller, and the bractlets are broadly elliptical and enlarge 
in fruit, as in P. fragiformis, from which it differs mainly in size, 
being in every respect smaller, and in the fact that the flowering 
stems scarcely exceed the leaves. A connecting link is formed by 
the Greenland P. Friesiana, which resembles P. nana in every 
respect, except that the flowering stems are elongated, as in P. 
Jragiformis. Probably all three are but forms of one species. P. 
nivea arctica, at least as to Richardson’s plant, must be included 
in P. nana. It ranges through arctic America from Labrador 
to Alaska, and is also found in eastern Siberia. 
POTENTILLA FRAGIFORMIS Willd. Mag. Gesell. Naturf. Fr. Berl. 7: 
294. 1813. 
Differs from P. zana in being in every respect more robust 
and with stems 1-2 dm. high. It somewhat approaches P. villosa 
in habit, but lacks the tomentum and has much smaller flowers. 
It comes nearest the Caucasian and Siberian P. gelida Meyer, but 
differs in its hirsute pubescence. P. fragiformis is mainly Siberian, 
but has been collected on the Aleutian Islands. 7 
