MEMOIRS FROM THE DEPARTMENT OF BOTANY OF COLUMBIA UNIVERSITY U® 
therefore taken as the type; the other somewhat approaches P. Blaschkeana in the gen- 
eral habit and the size of the flowers, and may be known under the name: 
55. Potentilla ctenophora. 
Potentilla gracilis var. flabelliformis Torr. Bot. U.S. Expl. Exp. 289. In part. Wats. 
King’s Exp. 5: 88. In part. 
Potentilla gracilis Holz. Contr. U. 8. Nat. Herb. 3: 223. In part. 
Potentilla flabelliformis ctenophora Rydb. Bull. Torr. Bot. Club, 24: 7. 1897. 
ILLUSTRATION: Pate 28, f. 6, outline of basal leaf. 
Stem stout, erect, 5-7 dm. high, sparingly silky-strigose or somewhat villous. 
Stipules about 2 cm. long, entire or deeply toothed. Basal leaves with petioles 1.5-3 
dm. long, digitately 5—7-foliolate, sparingly silky above, more or less densely white- 
tomentose beneath. Stem leaves similar, but short-petioled or sessile ; leaflets 5-10 em. 
long, oblanceolate, divided to near the midrib into broadly linear acute segments, the mar- 
gins not revolute. Cyme rather dense, with short branches. Flowers 1.5—2 em. in diam- 
eter. Hypanthium densely silky ; bractlets lanceolate, much shorter than the broadly 
ovate sepals. Petals broadly obcordate, bright yellow, much exceeding the sepals. Sta- 
mens about 20. 
This stands near to P. Blaschkeana, but I think it is without doubt a good species. 
T have had the opportunity to watch the two in the field and saw them often growing 
together, but never found an intermediate form, and in all the collections that have 
gone through my hands there are only the specimens from one locality, where I am in 
doubt as to which species to refer them, and these may be hybrids. 
It is nearer related to the preceding species, and perhaps should rather be re- 
garded as a variety of it, as intermediate forms are not lacking. The typical form of 
P. ctenophora is very unlike that of P. flabelliformis, differing in larger flowers, shorter 
and denser cyme, broader segments of the leaves, and by the fact that their margins are 
never revolute. The range of the two species is nearly the same, extending from Wvyo- 
ming and Saskatchewan to British Columbia and Northern California. 
S10. SUBJUGAE. 
56. Potentilla subjuga Rydberg. 
Potentilla subjuga Rydberg, Bull. Torr. Bot. Club, 23: 397. 1896. 
Innustrations: Bull. Torr. Bot. Club, 23: pl. 274. Puare 29, f. 1; fruiting hy- 
v oe Siete 
vanthium and calyx, f. 2; dissection of flower, f. 3; pistil, f£ 4; stamen, f. 5. 
: Fie ] ai fe 
Tufted, from a perennial root ; stems many, 1-3 dm. high, silky-villous, few-leaved, 
rather divergently branched above, the lower portion covered with the brown scarious 
