ROSACEAE (ROSE FAMILY) 261 



slender, glabrous, 2-3 dm. high: leaves mostly basal, interruptedly pinnate; 

 leaflets 5-9, oblong-cuneate, incisely few-toothed above, glabrous except for 

 a few ciliolate hairs, dark green, the terminal one petiolulate, the others slightly 

 decurrent on the rachis : cyme paniculately branched : sepals woolly-pubescent 

 at base, sharply acuminate, only 5 mm. long, twice as long as the minute 

 linear bractlets: petals broadly obovate, ret use, barely surpassing the calyx: 

 achenes glabrous but imbedded in the wool of the receptacle. In cliff crev- 

 ices; northern Colorado. 



34. Potentilla crinita Gray, Mem. Am. Acad. 1849: 41. Stems few from 

 thecaudex, ascending, silky-pilose: leaves short-petioled, pinnately 9-1 5-foli- 

 olate, green but silky-villous below, glabrate above; leaflets oblong-cuneate, 

 crowded, toothed at summit, the white silky pubescence of the under side 

 projecting beyond the tip of the teeth in a soft tuft; stipules ovate-lanceolate, 

 acuminate: the acute bractlets a little shorter than the ovate-lanceolate 

 sepals, which are surpassed by the obovate deeply retuse petals. On the dry 

 plains; southern Colorado to Arizona. 



35. Potentilla effusa Dougl. Lehm. Stirp. Pug. 2: 8. 1830. Stems nu- 

 merous from the same crown, ascending or diffuse, silky-tomentose, becoming 

 glabrate, more or less branched: leaves white-tomentose on both sides, in- 

 terruptedly and irregularly 5-13-foliolate; leaflets obovate or cuneate-oblong, 

 the upper often confluent, toothed with rather broad teeth; stipules lanceolate, 

 subentire: flowers many in a paniculate cyme: calyx tomentose; the sepals 

 lanceolate acuminate, nearly twice as long as the slender bractlets and nearly 

 equaling the obcordate petals. (P. color adoensis Rydb. Monog. Pot. 1. c. 115.) 

 On the dry plains; New Mexico to British America. 



36. Potentilla Hippiana Lehm. 1. c. 2: 7. 1830. Stems many from the 

 crown, ascending or nearly erect, white with appressed hairs, 2-4 dm. high: 

 leaves greenish and appressed-silky above (not tomentose), silky and tomen- 

 tose beneath, pinnately f ew-f oliolate ; leaflets obovate or cuneate-oblong, ob- 

 tusely toothed, smaller toward the base of the leaf, sometimes a little de- 

 current upon the rachis; stipules long, ovate-lanceolate, acute, subentire: 

 flowers in a rather short dichotomously branched cyme: calyx silky; the se- 

 pals ovate-lanceolate, acute, scarcely longer than the similar birt narrower 

 bractlets: petals 6-8 mm. long, obovate, retuse, longer than the calyx. (P. 

 propinqua Rydb. Bull. Torr. Bot. Club 28: 176. 1901; P. filicaulis Rydb. 

 Bull. Torr. Bot. Club 24: 2. 1897.) In the moist parks of the mountains; 

 New Mexico to British America. 



37. Potentilla ambigens Greene, Erythea 1: 4. 1903. Stems few, assur- 

 gent, stout, 4-7 dm. high, silky-villous with spreading hairs: leaves large, ir- 

 regularly pinnate, 9-1 5-f oliolate, silky-villous on both sides but more densely 

 so below; leaflets oblong-obovate, coarsely serrate, more or less decurrent on 

 the petiole and the uppermost often confluent; stipules large, subentire or 

 toothed: flowers in a long, rather narrow cyme, the branchlets and pedicels 

 often long and slender: bractlets and sepals lanceolate, subequal, exceeded 

 by the obcordate petals. Infrequent; middle altitudes; New Mexico to 

 Wyoming. 



24. COMARUM L. 



Perennial herbs, resembling Potentilla, with pinnately 5-7-foliolate leaves 

 and cymose flowers. Bractlets, sepals, and petals 5. Receptacle becoming 

 enlarged and spongy in fruit. Pistils numerous; the style lateral and fili- 

 form. 



1. Comarum palustre L. Sp. PL 502. 1753. Stems stout, ascending from 

 a decumbent base, glandular-pubescent above: leaves green above, lighter 

 beneath and more or less pubescent; the leaflets oblong, the pairs closely ap- 

 proximate; stipules large, the lower amplexicaul and long-adnate: flowers in 

 an open cyme: sepals purplish, in fruit 1-2 cm. long, much exceeding the 

 linear bractlets: petals red, ovate, acute, much shorter than the sepals: 

 stamens with fleshy filaments, inserted on the margin of the thickened disk: 



