436 ROSACEiE. Pote.ntilla. 



20. POTENTILLA. Linn. gen. p. 255 ; Juss. gen. p. 338. 



Fotentilla &- Tormentilla, Linn. Potentilla, Nestl. <J- Lehm. excl. Comarum, 



Calyx concave at tlie bottom, deeply 4-5-clett, with 4-5 alternate exterior 

 segments or bracteoles. Petals 4-5, obtuse or obcordate, deciduous. Sta- 

 mens numerous, inserted into the inargin of the usually hairy disk which 

 lines the base of the calyx : filaments filifomi or subulate. Ovaries numer- 

 ous, collected into a head on the flattish persistent dry villous receptacle : 

 styles either lateral or nearly terminal, deciduous : stigmas obtuse or some- 

 what capitate : ovule always inserted next the insertion of the style, and ac- 

 cordingly either suspended or ascending. Achenia numerous. Radicle 

 always superior. — Herbaceous or suffruticose plants, with ])innately or pal- 

 mately compound leaves. Stipules of the lower leaves adnate to the petiole. 

 Flowers solitary or cymose, yellow or white, rarely red or purple. 



This genus presents some diversities in respect to the style and ovule, which 

 eeem to have escaped notice hitherto. 



§ 1. Style terminal or nearly so, or inserted above the 7nid die of the ovary i 

 seed anatropous, susjjended or p)endulous. — Eupotentilla. 



Tliiss division, w'nich comprises by far the greater part of the genus, contains two 

 obvious sections, viz : Potentillastrum, Seringe (excl. spec), including the species 

 with glabrous carpels (which are sometimes hairy at the insertion) and mostly yel. 

 low flowers: and Fragariastrum, iSen'w^e (excl. spec), including those with vil. 

 lous or comose carpels, the receptacle being also densely villous, and chiefly white 

 or reddish flowers. There are, we believe, no true species of the latter section in 

 North America. The former might perhaps be best subdivided by means of char- 

 acters taken chiefly from the style ; which in P. Pennsylvanica and all its allies, 

 P. recta, and tbe allied species, P. Norvegica, supina and many others, is short, 

 rather fleshy or perhaps glandular, and thicker at the base where it is articulated 

 with the apex of the ovary, or is slightly lateral. In P. verna, aurea. Canadensis, 

 and the species most resembling these, the style is longer, filiform, and more per- 

 sistent, not thickened but usually attenuated at the base, and inserted below the 

 apex of the ovary. A pretty complete series may however be traced between 

 these and the preceding forms : and P. Anserina is intermediate in structure be- 

 tween them and those with almost basal styles, and ascending nearly orthotropous 

 ovules. The character of: Style lateral and seed suspended, generally given to Po- 

 tentilla, is almost wholly incorrect ; for whenever the insertion of tbe style is deeply 

 lateral, the seed is ascending. — All our species of this section have yellow flowers. 



* A7inual or biennial (achenia mostly striate or ribbed). 



--/ — 1j p. Norvegica (Linn.): hirsute; stem erect, at length dichotomous 

 ' above ; leaves palmately 3-foliolate, the cauline ones on very short petioles ; 

 leaflets obovate-oblong, the uppermost lanceolate, coarsely and incisely ser- 

 rate ; stipules ovate-lanceolate, mostly entire ; cyme leafy ; the alar i)edicels 

 elongated ; calyx-segments longer than the obovate emarginate (pale yellow) 

 petals ; achenia rugose-cost ate or striate, sometimes almost even. — ~Linn. ! 

 spec. 1. p. 449 ,- Fl. Dan. t. 171 ; Michx. ! fi. 1. p. 302 ; DC. ! I. c. ; Hook. ! 

 I. c. ; Darlingt. ! fl. Cest. p. 303. 



p. stem less branched, leafy ; petals very pale yellow. — P. Monspeliensis, 

 JLinn. P. hirsuta, Michx. ! I. c. ; Pursh .' I. c. ; Hook. ! 1. c. P. Morisoni, 

 DC! I.e. ■ 



