13 
decidedly lenticular, while in P. Anserina the upper end is thicker 
and rounded-triangular in cross-section. 
P. Egedi is an arctic species, found from Greenland to Alaska, 
and extending southward on the coasts to Maine and Oregon. 
The /ruticosae differ from the other groups of North American 
Potentillae in the following respects: The style is lateral, ovule 
ascending, achene hairy and the plant more or less shrubby. The 
American species are: 
POTENTILLA FRUTICOSA L, Sp. Pl. 495. 1753. 
This is a native of the north temperate zone, extending in 
America from Labrador to Alaska south to New Jersey and Colo- 
rado. . In mountain regions the leaflets are narrower with revolute 
Margins, and this form represents P. floribunda Pursh, P. fruti- 
cosa tenuifolia Lehm. The extreme is reached by the form col- 
lected by Watson during the King’s expedition and described as. 
P. fruticosa parvifolia Nats. It has nearly linear leaflets and 
smaller long-pedicelled flowers. 
POTENTILLA TRIDENTATA Soland.; Ait. Hort. Kew. 2: 216. 1789. 
P, retusa Retz. is generally cited as a synonym of P. tridentata 
and is much older, but P. retusa is described as having yellow flow- 
ers, and in the figure of it in Flora Danica the petals are also yel- 
low, while in P. tridentata, as is well known, they are white. If 
made from a specimen of -P. tridentata it is, indeed, a very poor 
one, as it resembles Siééaldia procumbens more than P. tridentata. 
It can, however, not represent that species, as the petals exceed 
the sepals. What P. retusa was, or is, is still a secret. ’ 
P. tndentata extends from Greenland to the mountains of N orth. : 
Carolina and westward to Minnesota. 
Biflorae. This contains only one species, placed by Lehmann 
with P. fruticosa, P. tridentata and their allies. The style is, how- 
€ver, nearly terminal, and the achenes not hairy. It resembles the 
Fruticosae i in the thickish leaves, whose margins are entire, and the: 
non-emarginate petals. The receptacle has also very long hairs. 
POTENTILLA BIFLORA Willd.; Schlecht. Mag. Gesel. Nat. Fe 
Berlin, 7: 297. 1813.. ie 
It is a native of northeastern Asia, Alaska and the arctic coast — 
of North America, but a rather rare plant. . sie 
