428 ROSACEAE 



amphitropous or orthotropous. [Name diminutive of potens, powerful, from the medicinal 

 properties of some species.] 



About 300 species, native of the north temperate zone. Type species, Potentilla reptans L. 



Styles terminal to lateral; ovules anatropous or amphitropous. 

 Styles terminal or subterminal; ovules pendulous. 



Flowers solitary, axillary, long-peduncled ; 4-merous. 1. P. procumbent. 



Flowers cymose; 5-merous. 



Styles fusiform and glandular. 



Annuals or biennials; cymes leafy, many-flowered. 

 Leaflets toothed. 



Achenes gibbous on the inner side; leaves pinnate. 2. P. paradoxa. 



Achenes not gibbous; leaves 3-foliolate or the lower pinnately 5-foliolate. 



Leaves pinnately 5-foliolate below, 3-foliolate above. 3. P. rivalis. 



Leaves all 3-foliolate. 



Stems soft-pubescent; stamens usually 10; petals about half the length of 

 the sepals. 

 Low, diffusely branched; the branches decumbent; soft-pubescent or 

 glabrate. 4. P. millegrana. 



Erect, 3-5 dm. high, soft glandular-pubescent. 5. P. biennis. 



Stems stout, erect, hirsute below; stamens 15-20; petals about equaling the 

 sepals. 6. P. monspeliensis. 



Leaflets divided to near the base into 3-5 linear segments. 7. P. Ncwberryi. 



Perennials, cymes not very leafy, few-flowered; leaves odd-pinnate. 8. P. pseudosericea. 



Styles filiform, not glandular at base; perennials. 

 Leaves digitate, see also P. diversifolia. 

 Basal leaves with 5-9 leaflets. 

 Plants erect or ascending. 



Leaflets white-tomentose beneath. 



Leaflets toothed or lobed scarcely half way to the midrib, the teeth oblong 

 to lanceolate. 



Leaflets densely white-tomentose beneath; stems slender. 



9. P. gracilis. 



Leaflets grayish, rather sparsely tomentose beneath; stems stout. 



10. P. glomerata. 

 Leaflets toothed well beyond half way to the midrib. 



Plants 4-8 dm. high; leaflets with short tomentum. 



Lobes of the leaflets about 1 cm. long, oblong-linear, scarcely 

 revolute. 11. P. Blaschkeana. 



Lobes of the leaflets extending almost to the midrib, 1-2 era. long, 

 narrowly linear and revolute. 12. P. flabelliformis. 



Plants scarcely 2 dm. high, more or less densely villous-tomentose 

 throughout. 15. P. fastigiata. 



Leaflets more or less silky-pubescent beneath, not tomentose, more or less glandu- 

 lar atomiferous. 



Leaflets strongly nerved, oblanceolate, sparsely appressed-pubescent beneath. 



13. P. Nuttallii. 



Leaflets not strongly nerved, obovate; more or less densely silky-pubescent 

 beneath. 14. P. etomentosa. 



Plants prostrate or nearly so, silky-villous and more or less glandular throughout; 



leaflets 5, crenate at the summit. 16. P. Wheeleri. 



Basal leaves 3-foliolate. 



Leaves more or less tomentose beneath. 



Stems 1-2-flowered; leaflets deeply lobed. 17. P. uniflora. 



Stems several-flowered; leaflets crenate-serrate, Fragaria-like. 



Leaves sparsely pubescent or glabrate. 

 Leaves odd-pinnate, or digitate in P. diversifolia. 

 Petals acutish or acuminate at the apex. 

 Petals rounded or emarginate at the apex. 



Leaflets digitate or a few odd-pinnate, 5-7, deeply cleft. 

 Leaflets strictly odd-pinnate. 

 Leaves with 3-5 leaflets. 

 Leaflets 5. 



Leaflets 3, the terminal long-petiolulate. 

 Leaves with 7 or more leaflets. 



Leaves canescent, silky or tomentose at least beneath. 

 Leaves green and glabrate or merely strigose. 



Pedicels at least in fruit recurved; stems diffuse or spreading. 



Stems and petioles rather copiously villous with long ascending or 

 spreading hairs. 25. P. klamathensis. 



Stems and petioles sparingly strigose with short appressed hairs. 



Bractlets lanceolate, acute, equaling the lobes or nearly so. 



26. P. millefolia. 



Bractlets oblong-elliptical, obtuse, much shorter than the lobes. 



27. P. Hickmanii. 



Pedicels straight and erect or ascending; stems erect or ascending. 

 Leaflets 5—11. 28. P. Drummondii. 



Leaflets 17-27. 29. P. multijuga. 



