KOSACEAE (ROSE 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. Radicle superior. Herbs, or rarely shrubs, with com- 

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



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



ice reputed medicinal powers.) 



Petals reddish-purple 

 Petals yellow or white l>. 

 l>. Stems shrubby 

 b. Steins herbaceous c. 



14. P.palustris. 



15. P.fruticosa. 



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

 leaves or on the stolons. 



Leaves pinnate, of numerous leaflets 17. P. Anserina. 



Leaves palmate, of 3-5 leaflets. 



Tufted alpine plant 11. 7*. RobUnsiana. 



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. canadensis. 

 Steins repent. 

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



tate nearly to the base 20. P. reptans. 



Leaflets mostly 8, cuneate-obovate, coarsely incised 



chiefly above the middle 21. P. procumbent*. 



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



leaves d. 

 (I. Leaves pinnate. 



Inflorescence glandular-viscid 1. P. arguta. 



Inflorescence not glandular. 

 Leaves white-pubescent above. 

 Pubescence of the leaves lustrous and silky . . .12. P. Hippiana. 



Pubescence a dull tomentum 13. P. effusa. 



Leaves green or greenish above. 

 Leaves definitely pinnate, the leaflets essentially uniform ; 



cyme very leafy 4. P. paradoxa. 



Leaves seemingly palmate, the leaflets crowded and the 

 lower ones much smaller than the others. 



Cyme very leafy ; petals minute 

 Cyme scarcely leafy ; petals shov 

 palmate e. 



. , petals showy .... 

 Leaves palmate e. 



9. Petals white ; leaflets toothed only at tip 



s. 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 stein hirsute. 



Leaflets 8 ; petals about as long as the calyx-lobes 

 Leaflets 5-7 ; 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 i. 

 i. 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 

 i. Plants with simple stems and scarcely leafy corymbi- 

 form cvrnes 



3. P.rivalis. 



6. P. pennttylvanica. 



16. P. tridentata. 



11. P. Robbinsiana. 



: 



cy 

 (l 



I 



2. P. monspeliensis. 

 10. P. recta. 



1. P. argentea. 



8. P. intermedia. 



5. P. Nicolletii. 



3. P. rivalift. 



9. P. Nuttallii. 



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



ous ; inflorescence cymose. 



Style nearly basal; stamens 25-30; perennial <jlandular-villous herbs, with 

 pinnate leaves, and father large white or yellow petals. 



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

 ry, 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 P. C., and 

 estw. June, July. 



GRAYS MANUAL 



