10 
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The 7ormentillae are a small group, characterized by the more or 
less spreading, prostrate or creeping stem and long-pedicelled, ax- 
illary flowers. The original Zormentillae have 4-merous flowers, 
but sometimes, however, they are 5-merous, and other species that 
have regularly 5-merous flowers have no other character which 
would warrant the division into two. groups, much less into two 
genera. The group is mainly European, only one species being 
a native of North America, viz.: 
POTENTILLA CANADENSIS L. Sp. Pl. 498. 1753. 
It is a very variable plant, and several species have been pro- 
posed. What I take as the original ?. Canadensis is a less Juxu- 
riant form of what has generally been known as P. Canadensis sim- 
plea (Michx.) T. & G. (P. simplex Michx.), not that small, simple, 
more hairy form, only a few inches high, that grows in poor dry soil, 
which is 
POTENTILLA CANADENSIS PUMILA (Poir.) T. & G. Fl. N. Am. 1: 
443. 1840. 
Potentilla pumila Poir. in Lam. Enc. Meth. 5: 594. 1804. 
P. Canadensis is common from Maine and North Carolina to 
Indian Territory and Minnesota. I have seen one specimen col- 
lected in Nevada, but this was undoubtedly introduced. The variety 
has about the same range, but is rarer. 
POTENTILLA REPTANS L. Sp. PI. 499. 1753. - 
This European species has been collected by Martindale in 
1876 on ballast in New Jersey. It differs from P. Canadensis in 
the creeping and rooting stem, smaller leaves and large, ovate or 
elliptical bractlets, which exceed the sepals. 
POTENTILLA NEMORALIS Nestler, Mon. Pot. 28 and 65. 1816. 
Tormentilla reptans L. Sp. Pl. 500. 1753. Not Pote.tilla 
reptans L.. 
Also a European species which has been collected in Labrador. 
It differs from P. Canadensis in the 4-merous flowers and in the 
leaves, which are all, except the basal ones, ternate. 
Haematochri. The dark purple- or dark red-flowered species. 
of Potentilla constitute a very natural group, which consist of the _ 
