ROSACEA.E (ROSE FAMILY) 481 



16. POTENTiLIiA L. Cinqubpoil. Five-finger 



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

 ing 10-cleft. Petals 6, usually roundish. Stamens many. Achenes many, col- 

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

 or terminal, deciduous. Radicle 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. Ansei'ina, from its 

 once reputed medicinal powers.) 



.7. Petals reddish-purple 14. P. palusi/ris. 



1. Petals yellow or white 6. 



6. Stems shrubby ... 16. P.fruticosa. 



J>. 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 17. P. Ariserina. 



Leaves palmate, of 8-5 leaflets. 



Tufted alpine plant 11. P. Sobbinsiana 



Plants with elongate slender stems. 

 Earliest flower from the node above the first well-developed 



internode 18. P. pumila. 



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

 developed internode. 

 Stems ascending or procumbent, not repent . . .19. P. canadenais. 

 Stems repent. 

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



tate nearly to the base 20. P. r&ptan^. 



Leafiets mostly 3, cuneate-obovate, coarsely incised 



chiefly above the middle 21. P. prommibenB. 



c. FJowers cymose, or if solitary in the axils of reduced upper 

 leaves d. 

 d. Leaves pinnate. 



Inflorescence glandular-viscid 1. P. arguta. 



Inflorescence not glandular. 

 Leaves white-pubescent above. 

 Pubescence of the leaves lustrous and silky . . .12. P. Il^piana. 

 Pubescence a dull tomentum ... . IS. P. e;g^a. 



Leaves green or greenish above. 

 Leaves deflnitely pinnate, the leafiets essentially uniform ; 



cyme very leafy 4. P. pa/radoxa. 



Leaves seemingly palmate, the leaflets crowded and the 

 lower ones much smaller than the others. 



Cyme very leafy ; petals minute 8. P. rivalift. 



Cyme scarcely leafy ; petals showy . . . . 6. P. pennsylvanica 



d. Leaves palmate e. 



e. Petals white ; leaflets toothed only at tip 16. P. tridentata. 



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

 /, Tufted alpine plant with 1-2-flowered short branches . . 11. P. BobMnaiana. 

 f. Leafy-stemmed plants with cymose flowers g. 

 g. Petioles and lower p^rt of stem hirsute. 



Leaflets 3 ; petals about as long as the calyx-lobes 2. P. monspeUm-aia. 



Leaflets 5-7 ; petals much exceeding the calyx-lobes . 10. P. recta, 

 g. Petioles and stems woolly or tomentulose h. 



h. Leaves silvery-white beneath 1. P. argentea. 



A. Leaves green or at most slightly grayish beneath i. 

 i. Plants loosely branched, with very leafy difi'use cymes. 



Perennial ; petals obcordate 8. P. intermedia. 



Annual or biennial ; petals narrowly cuneate. 

 Achenes strongly gibbous on the ventral side 5. P. NicolletU. 



Achenes not gibbous on the ventral side . . 3. P. rvoatis. 

 i. Plants with simple stems and scarcely leafy corymbi- 



form cymes . . ... 9. P. NuttallU. 



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

 ous ; inflorescence cymose. 

 * Style nearly basal ; stamens 25-30 ; perennial glandular-vUlous herbs, with 

 pinnate leaves, and rather large white or yellow petals. 

 1. P. arguta Pursh. Stems erect, usually stout, 3-10 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. 



gkay's manual — 31 



