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, retuse, 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-foliolatc; 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. coloradoensis Rydb. Monog. Pot. 1. c. 115.) 

 On the dry plains; New Mexico to British America. 



36. Potentilla Hippiana Lclnn. 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 fe\v-foliolate; 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 but narrower 

 bractlets: petals <i S mm. long, obovate, retuse, longer than the calyx. (P. 

 propiw,un Rydb. Hull. Torr. Hot. Club 28: 17G. 1901; P. ftticaulis Rydb. 

 Bull. Torr. Hot. 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, 9-15-foliolate, silky-villous on both sides but more densely 

 so belo\y; 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. PI. 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: 



