280 EOSACE^. PoieniiUa. 



9. P. gelida, C. A. Meyer. Nearly glabrous, the pubescence minute or villous : 

 stems low, slender, 1 - 3-flowered : leaflets very broadly cuneiform, 6 to 9 lines long, 

 rounded at the apex and coarsely 7 - 9-toothed ; terminal leaflet shortly petiolulate : 

 bractlets and calyx-lobes nearly equal, obtuse or acute : petals 2 or 3 lines long, a 

 little exceeding the calyx : carpels numerous. • — Watson, 1. c. 559. P. fiahelUfolia, 

 Hook. ; Torr. & Gray, El. i. 442; Lehm. Revis. 153, t. 51. 



In the Sierra Nevada at Summit {Bolander) and on Lassen's Peak (/. G. Lcmmon), and north- 

 ward to Washington Territory ; also in Northern Asia. 



* * * Style filiform, attached at or below the middle of the ovary : leaves pinnate : 

 fixnvers yellow : receptacle small, villous. 



-i- Herbaceous, stoloniferous and creeping : akenes glabrous : flowers axillary, solitary. 



10. P. Anserina, Linn. White-tomentose and silky-villous : leaves all radical, 

 often a foot long or more ; leaflets 3 to 10 pairs, with smaller ones interposed, 

 oblong, sharply serrate, tomentose at least beneath ; stipules many-cleft : bractlets 

 often incised, about equalling the calyx-lobes : petals 3 to 6 lines long, exceeding 

 the calyx : stamens 20, rarely 25 : carpels 20 to 40 ; the style attached to the mid- 

 dle : receptacle very villous. 



On stream banks ; frequent throughout North America, as also in South America and the Old , 

 World. Very varialjle in size and amount of pubescence. 



+- +- Shrubby : akenes villous : flowers terrninal, cymose or solitary. 



11. P. £rilticosa, Linn. Much branched, 1 to 4 feet high, silky-villous: stip- 

 ules scarious ; leaflets 5 to 7, oblong-lanceolate, entire, approximate, 2 to 12 lines 

 long, lighter colored beneath and the margin revolute : petals 2 to 6 lines long, ex- 

 ceeding the calyx : stamens 30 : carpels 20, very villous, the style attached below 

 the middle. 



In the Sierra Nevada from Ebbett's Pass northward, and throughout the northern portion of 

 North America. Also frequent in the Old World. 



* * * * Styles flliform, attached to the middle of the numerous glabrous carpels, 

 ivhich are sessile upo7i a large spongy receptacle ; herbaceous perennial, with large 

 purple flowers and pinnate leaves. 



12. P. palustris, Scop. Stems stout, ascending from a decumbent rooting 

 perennial base : nearly glabrous : leaflets 5 to 7, oblong, an inch or two long, ser- 

 rate : flowers few, in an open cyme : cal^'x puri)lish, 6 to 10 hues long in fruit; 

 bractlets linear, much shorter : petals spatulate, acute, 2 or 3 lines long : stamens 

 20, upon the margin of the thickened disk. — Comarum pcdustre, Linn. 



Collected only in Sierra County, by J. G. Lcmmon. More frequent northward from Paget 

 Sound to Alaska, and eastward across the continent. 



15. SIBBALDIA, Linn. 



Petals linear-oblong, minute. Stamens 5, alternate with the petals ; filaments 

 very short. Carpels 5 to 10 : styles lateral : ovule ascending. Otherwise as Poten- 

 tilla. — Dwarf and cespitose arctic or alpine perennials ; leaves thick, trifoliolate, the 

 leaflets few-toothed at the truncate summit ; flowers cymose, yellow. 



Of the 4 or 5 Asiatic species the following is also European and American. 



1. S. procumbens, Linn. Somewhat villous : stems creeping, leafy at the 

 extremities: leaflets cuneate, 3-5-toothed, 3 to 12 lines long: peduncles usually 

 shorter than the leaves: calyx-lobes 1 to IJ lines long; bractlets linear and shorter: 

 l)etals much shorter, acute : akenes on very short hairy stipes. 



In the Sierra Nevada from Mt. Dana, at 12,500 feet altitude (Bol.anclcr), to Lassen's Peak 

 (Lcmmon) and Mt. Shasta, at 8,400 feet, Brewer. Also in the Rocky Mountains of Colorado, 

 and the White Moimtains, and northward to Alaska and Greenland. 



