178 ROSACE^E. Potentffla. 



ovule solitary, ascending or suspended. Akenes small, turgid, crustaceous, usually 

 sessile, upon a dry more or less elevated receptacle. Radicle superior. Herbaceous 

 or rarely woody ; leaves pinnate or digitate with distinct leaflets ; stipules adnate to 

 the petioles ; flowers cymose, or axillary and solitary. Lehmann, Revis. Potent. ; 

 Watson, Proc. Am. Acad. viii. 549. 



A genus of about 120 species, according to Bentham & Hooker (who include in it also the next 

 three genera), confined almost exclusively to the temperate and cold regions of the northern 

 hemisphere. The species are very variable, and many more than this number have been pub- 

 lished. Of the 30 or more native to North America, a dozen are also indigenous in Europe or 

 Northern Asia. 



* Styles fusiform, thickened and glandular at base : carpels very numerous, glabrous : 



flowers cymose. 



1. P. glandulosa, Lindl. Perennial, erect, a foot or two high, somewhat glan- 

 dular-villous, branched above : leaves pinnate ; leaflets 5 to 9, rounded, ovate, or 

 somewhat rhomboidal, coarsely serrate, an inch or two long : cymes at length open 

 and pedicels slender, the upper leaves and floral bracts conspicuous : calyx 4 to 6 

 lines long, somewhat tomentose and usually villous with coarse hairs ; bractlets 

 linear to oblong, shorter than the lobes : petals yellow or sometimes white, usually 

 shorter than the calyx : stamens 25, in one row on the margin of the thickened 

 disk: style attached below the middle of the ovary. Bot. Reg. t. 1583. P. Wran- 

 geliana, Fischer & Meyer ; Lehm. Revis. 49, t. 19. 



Var. Nevadensis, Watson. A slender form with small leaflets : inflorescence 

 more naked, the upper leaves and floral bracts being much smaller : calyx 2 to 4 

 lines long : flowers white or yellow : stamens occasionally only 20. 



From Monterey northward to Washington Territory ; the variety in the Sierra Nevada from 

 the South Fork of Kern River (Rothrock) to Oregon. P. fissa, Nutt., is a usually low and slender 

 form of this species with occasionally 5 pairs of leaflets, common in the Rocky Mountains ; it 

 does not appear to have been collected in California. 



2. P. rivalis, Nutt. Annual or biennial, erect or ascending, often diffusely 

 branched, softly villous with spreading hairs or nearly glabrous : leaves pinnate, 

 with 2 pairs of closely approximate leaflets, or a single pair and the terminal leaflet 

 3-parted ; upper leaves ternate ; leaflets cuneate-ovate to -lanceolate, coarsely serrate, 

 1 to 1| inches long : cymes loose, with slender pedicels : bractlets and calyx-lobes 

 equal, 1| to 3 lines long: petals minute, yellow: disk not thickened: stamens 10 

 to 20 : style terminal. Torr. & Gray, Fl. i. 437. 



Var. millegrana, Watson, 1. c. Leaves all ternate : akenes usually small and 

 light-colored. P. millegrana, Engelm. ; Lehm. Revis. 202 ; Watson, Bot. King 

 Exp. 85. 



The variety ranges from the eastern slope of the Sierra Nevada, and from Fort Mohave (Cooper), 

 eastward to New Mexico and the Missouri. The typical form is not found west of the Rocky 

 Mountains. 



* * Style filiform, terminal : carpels glabrous : stamens 20 : herbaceous perennials, 



with cymose yellow flowers. 



-{- Leaves pinnate or digitate, with 5 or more (rarely 3) leaflets : bractlets shorter 



tlutn the sepals. 



3. P. Breweri, Watson. Alpine, densely white-tomentose throughout, the calyx 

 and upper leaves silky-villous with appressed hairs : stems decumbent at base, 

 rather stout, 3 to 10 inches high : stipules broad, mostly incised; leaflets 7 to 13, 

 nearly uniform in size, 3 to 6 lines long, cuneate-obovate, deeply incised : cymes 

 mostly crowded : petals emarginate, 3 to 4 lines long, much exceeding the calyx : 

 carpels 20 to 25, on villous pedicels ; the receptacle and disk hairy. Proc. Am. 

 Acad. viii. 555. 



