ROSACEAE (llOSE FAMILY) 



481 



15. POTENTILLA L. Cinquefoil. Five-finger 



Calyx flat, deeply 5-cleft, with as many bractlets at the sinuses, thus appear- 

 ing 10-cleft. Petals 5, usually roundish. Stamens many. Achenes many, col- 

 lected in a head on the dry mostly pubescent or hairy receptacle ; styles lateral 

 or terminal, deciduous. Kadicle superior. — Herbs, or rarely shrubs, with com- 

 pound leaves, and solitary or cymose flowers ; their parts rarely in fours. (Name 

 a diminutive from potens, powerful, originally applied to P. Anserina, from its 

 once reputed medicinal powers.) 



a. Petals reddish-purple 



a. . Petals yellow or white h. 



b. Stems shrubb}- 



b. Stems herbaceous c. 

 c. Flowers solitary, on naked peduncles from the axils of the foliage- 

 leaves or on the stolons. 



Leaves pinnate, of numerous leaflets 



Leaves palmate, of 3-5 leaflets. 



Tufted alpine plant 



Plants with elongrate slender stems. 

 Earliest flower from the node above the first well-developed 



internode 



Earliest flower from the node above the second or third well- 

 developed internode. 

 Stems ascending or procumbent, not repent 

 Stems repent. 

 Leaflets mostly 5, spatulate-oblong, finely crenate-den- 



tate nearly to the base 



Leaflets mostly 3. cuneate-obovate, coarsely incised 



chiefly above the middle 



o. Flowers cymose, or if solitary in the axils of reduced upper 

 leaves d. 

 d. Leaves pinnate. 



Inflorescence glandular-viscid 



Inflorescence not glandular. 

 Leaves white-pubescent above. 

 Pubescence of the leaves lustrous and silky 

 Pubescence a dull tomentum ..... 

 Leaves green or greenish above. 

 Leaves definitely pinnate, the leaflets essentially uniform 



cyme very leafy 



Leaves seemingly palmate, the leaflets crowded and the 

 lower ones much smaller than the others. 

 Cyme very leafy ; petals minute .... 

 Cyme scarcely leafy ; petals showy 

 d. Leaves palmate e. 



e. Petals white ; leaflets toothed onh- at tip . 

 e. Petals yellow ; leaflets toothed along the sides /. 

 /. Tufted alpine plant with 1-2-flowered short branches . 

 /. Leafy-stemmed plants with cymose flowers g. 

 g. Petioles and lower part of stem hirsute. 



Leaflets 3 : petals about as long as the calyx-lobes 

 Leaflets r>-~ : petals much exceeding the calyx-lobes 

 g. Petioles and stems woolly or tomentulose h. 



h. Leaves silvery-white beneath 



h. Leaves green or at most slightly grayish beneath /. 

 *. Plants loosely branched, with very leafy diffuse cymes 

 Perennial ; petals obcordate .... 

 Annual or biennial; petals narrowly cuneate. 

 Achenes strongly gibbous on the ventral side 

 Achenes not gibbous on the ventral side 

 *. Plants \vith simple stems and scarcely leafy corymbi 

 form cymes 



14. P. palustris. 



15. P./ruticosa. 



17. P. Armerina. 

 11. P. Robbinsiana 



18. P. pumila. 



19. P. canadensis. 



20. P. reptans. 



21. P. procumbens. 



1. P. arguta. 



12. P. Ilippiana. 



13. P. effma. 



4. P. paradoxa. 



3. P. rivalU. 



6. P. pennsylvanica 



16. P. tridentata. 



11. P. Pobbinsiana. 



2. P. wonspeliensis. 

 10. P. recta. 



7. P. argentea. 



8. P. intermedia. 



h. P. Nicolletii. 



3. P. rivalis. 



9. P. NuitalUi. 



§ 1. Styles thickened and glandular toward the base ; achenes glabrmts, numer- 

 ous; inflorescence cymose. 



* Style nearly basal; stamens 25-.S0 ; perennial glandular-villous herbs, with 

 pinnate leaves, and rather large ichite or yellow petals. 



1. P. arguta Pursh. Stems erect, usually stout, 8-10 dm. high, brownish- 

 hairy, clammy above ; leaflets 7-11, oval or ovate, cut-serrate, downy beneath; 

 cyme strict and rather close ; stamens mostly 30, on a thick glandular disk. 

 {Drymocallis Rydb.) — Rocky, gravelly, or alluvial soils, e. Que. to D. C, and 

 westw. June, July. 



©rat's manual — 31 



