POTENTILLA. XLVIII. ROSACEA. 251 



minute, subulate ; sep. spreading, long-acuminate, shorter than the narrow-obo- 

 vate, emarginate petals; shj. 00. — A delicate house-plant, with snow-white 

 double flowers. Native of Mauritius. 



12. POTENTILLA. 



Lat. potcntia, power; in allusion to its supposed potency in medicine. 



Calyx concave, deeply 4 — 5-clcft, with an equal number of alter- 

 nate, exterior segments or bracteoles ; petals 4 — 5, obcordate ; sta- 

 mens 00 ; filaraeuts slender ; ovaries collected iuto a head on a small, 

 dry receptacle ; styles deciduous ; achenia GO. — Herbaceous or shrubby. 

 Lvs. finnately or falniately compound. Fls. solitary or cymose., mostly 

 yellow. 



* Leaves jpalviately trifoliate. 



1. P. NoRVEGiCA, Nonoegiaii Potentilla or CtnquefoU. 



Hirsute ; st. erect, dichotomous above ; Ifls. 3, elliptical or obovate, den- 

 tate-serrate, petiolulate ; q/ffies leafy; ca/. exceeding the emarginate petals. — 

 Old fields and thickets. Arc. Am. to Car. Stem 1 — 4t high, covered with silky- 

 hairs, terete, at length ibrlvcd near the top. Cauline petioles shorter than the 

 leaves. Leaflets J — IJ' by \ — *', (lower and radical ones very small,) often 

 incised. Stipules large, ov'ate, subentire. Flowers many, crowded, with pale 

 yellow petals shorter than the lanceolate, acute, hairy sepals. Jl. — Sept. 



0. ? hirsuta. T. & G. (P. hirsuta. Michx.) — Hairs loose, silky ; st. slender, 

 erect, subsimple ; lower and middle lvs. equal, long-petiolate ; Ifls. roundish-obo- 

 vate, sessile, incisely dentate ; fls. few, petals rather conspicuous, nearly as long 

 as the calyx. — Dry fields. With reluctance I adopt the views of Torrey & Gray 

 in regard to this plant. 



2. P. TRiDENTATA. Ait. Tridciit OX Mou7ilai7i Potentilla. 



Smooth ; st. ascending, woody and creeping at base ; Ifls. 3, obovate-cune- 

 ate, evergreen, entire, with 3 large teeth at the apex ; cytnes nearly naked ; pet. 

 twice longer than the calyx. — On the White Mis. ! and other alpine summits in 

 the N. States. Flowering stems 6 — 12' high, round, often with minute, ap- 

 pressed hairs. Petioles mostly longer than the leaves. Leaflets sessile, 9 — 18" 

 by 4 — 6", coriaceous, smooth. Flowers with white, obovate petals. Carpels 

 and achenia with scattered hairs. Jn. Jl. 



3. P. MINIMA. Haller. 



St. pubescent, ascending, mostly 1-flowered; lvs. trifoliate; Ifls. obovate, 

 obtuse, incisely serrate, with 5 — 9 teeth above ; pet. longer than the sepals. — 

 Alpine regions of the White Mts. Stems numerous and leafy, 1 — 3' high. 

 Leaflets with the margins and veins beneath hairy. Flowers small. Petals 

 obcordate. Bracteoles oval-obtuse, narrowed at the base. 

 * * Leaves palmatcly 3 or 5-foliate. 



4. P. Canadensis. (P. sarmentosa. Willd.) Comvion CinqxtefoU. 

 Villose pubescent ; st. sarmentose, procumbent and ascending ; lvs. pal- 



mately 5-foliate, the leaflets obovate, silky beneath, cut-dentate towards the 

 apex, entire and attenuate towards the base ; stip. hairy, deeply 2 or 3-cleft, or 

 entire; pedicels a.xi\\xvcj, solitary; bracteoles of the calyx longer than the seg- 

 ments, and nearly as long as the petals. — Common in fields and thickets, U. S. 

 and Can. Stems more or less procumbent at base, from a few inches to a foot 

 or more in length. Flowers yellow, on long pedicels. Calyx segments lanceo- 

 late or linear. Apr. — Aug. 



13. jniviila. T. & G. (P. pumila. Ph.) — ^Very small and delicate, flowering 

 in Apr. and May. — I cannot perceive any diflerence between this and the above, 

 except its diminutive size and early flowering. In dry, sandy soils. Stems 

 about 3' high. 



y. simple.c. T. & G. (P. simplex. Michx.)— Plant less hirsute ; st. simple, 

 erect or ascending at base; Ifls. oval-cuneiform; flowering in June — Aug. — In 

 richer .soils. Stems 8—14' high. Leaflets about 1' long, i as wide. 



5. P. ARGENTEA. SUvcry Clnqvefoil. 



St. ascending, tomentose, branched above ; Ifts. oblong-cuneiform, with a 

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