118 ROSACEA. (ROSE FAMILY.) 



11. POTEIVTILLA, L. Cinque-foil. Five-Finger. 



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

 ing 10-eleft. Petals 4 - 5, usually roundish. Stamens many. Achenia many, 

 collected in a head on the dry mostly pubescent or hairy receptacle : styles 

 lateral or terminal, deciduous. — Herbs, or rarely shrubs, with compound leaves, 

 and solitary or cymose flowers. (Name a kind of diminutive from potens, pow- 

 erful, alluding to the reputed medicinal power, of which in fact these plants 

 possess very little, being merely mild astringents, like the rest of the tribe.) 



§ 1. Style terminal, or attached above the middle of the ovary : achenia glabrous. 



# Annuals or biennials: petals pale yellow, small, not exceeding the calyx: receptacle 



globular, ovoid, or even oblong in fruit. 



1. P. Norvegica, L. Hairy, erect, branched above; leaves palmately 3- 

 foliolate; leaflets obovatc-oblong, cut-toothed. — Fields: common, especially 

 northward. A homely weed. (Eu.) 



2. P. paradoxus, Nutt. Somewhat pubescent, spreading or decumbent, 

 branched; leaves pinnate ; leaflets 5-9, obovate-oblong, cut-toothed; achenia 

 with a thick appendage at the base. — Banks of the Ohio and Mississippi. 



* * Perennicd herbs : petals yellow, commonly longer than the calyx. 

 ■*- Low: leeives palmate, of 3 or 5 leaflets. 



3. P. frigida, Vill. Dwarf (l'-3' high), tufted, villous when young, 

 stems or scapes mostly 1 -flowered; leaflets 3, broadly ivedge-oboveite, deeply cut into 

 5-7 oblong approximate teeth. (P. Robbinsiana, Oakes.) — Less villous with 

 age and smaller-flowered than P. frigida of the Alps, but agreeing closer with it 

 than with P. minima, which probably is only another form of the same species. 

 Alpine summits of the high mountains of New Hampshire. (Eu.) 



4. P. Caasatfciisis, L. (Common Cinque-foil or Five-Finger.) 

 Hairy or pubescent, procumbent and ascending, producing runners ; peduncles axil- 

 lary, elongated, l-flowered; leaflets 5, oblong or obovate-wedgc-form, cut-toothed 

 towards the apex. (P. sarmentosa, Muhl.) — Var. 1. pumila is a dwarf, early- 

 flowering state, in sterile soil. Var. 2. s/mplex is a taller and greener state, 

 with slender ascending stems. (P. simplex, Michx.) — Abounds among grass 

 in dry fields, &c. April - Oct. 



5. P. argentca, L. (Silvery Cinque-foil.) Stems ascending, 

 cymose at the summit, many-flowered, white-woolly ; leaflets 5, wedge-oblong, al- 

 most pinnatifid, entire towards the base, with revolute margins, green above, 

 white with silvery wool beneath. — Dry barren fields, &c. June - Sept. (Eu.) 



+- ■*- Tedler : leaves pinnate, of 3-9 leaflets. 



6. P. Penasylvanica, L. Stems erect, hairy or woolly ; cymose at 

 the summit, many-flowered ; leaflets 5-9, oblong, obtuse, pinnatifid, silky- wool- 

 ly with white hairs, especially beneath, the upper ones larger and crowded ; 

 petals scarcely longer than the calyx. — Pennsylvania 1 New Hampshire (Isle oi 

 Shoals, Bobbins), Maine (Cape Elizabeth, C. J. Sprague), and northward. July. 



§ 2. Style deeply lateral, attached at or beneath the middle of the ovai-y : petals yellow 



or white, deciduous. 



