POTENTII.LA.] ROSACES. 115 



ventral or basal ; ovule 1, pendulous. Achenes many, on a dry receptacle. 

 DISTIIIB. N. temp., Arctic, and mountain regions, 2 are found in the 

 south ; species 120. ETTM. Potens, from the powerful medicinal effects 

 attributed to some. 



SECTION 1. Trichothal'amus, Lehm. (gen.). Shrubby. Petals 5, orbi- 

 cular, yellow. Achenes many, hairy, on a very hispid receptacle. 



1 . P. frutico'sa, L. ; silky, leaves subdigitately-pinnate. 



Rocky banks by rivers, local ; Upper Teesdale, Durham, Cumberland, West- 

 moreland ; N. Clare and Gralway ; fl. June-July. A much-branched, leafy 

 shrub, 2-4 ft. ; bark flaking. Leaves oblong or lanceolate ; leaflets 3-5, 

 i f in. ; margins entire, revolute ; stipules entire. Flowers 1-1^ in., few, 

 in terminal subcorymbose cymes, golden yellow, sub-1-sexual ; bracts 

 lanceolate, longer than the ovate calyx-segments. DISTRIB. N. Europe 

 (Arctic), Siberia, W. Asia to the Himalaya, E. and W. N. America. In 

 Teesdale the flowers appear to be functionally 1- sexual ; those of the sexes 

 differ in appearance. 

 SECTION 2. Coma rum, L. (gen.). Petals 5, small, oblong-lanceolate, 



acuminate, purple-brown. Stamens many. Ac/ienes many, glabrous, on a 



conical dry spongy downy receptacle. 



2. P. Coma'rum, Nestl. ; leaves pinnately 5-7-foliolate. Comarum 

 palustre, L. 



Bogs and marshes, ascending to nearly 2,800 ft. in the Highlands ; fl. June- 

 July. Sparingly hairy. Rootstock long, woody; roots fibrous. Stems ^-1 J ft., 

 ascending, purple-brown. Leaves 2-4 in. ; leaflets 1^2 in., narrow-oblong, 

 obtuse, coarsely serrate, pale below ; stipules large, membranous, free portion 

 often cut. Flowers 1-1^ in. diam., few. Bracts smaller than the ovate-lanceo- 

 late acuminate sepals, purplish ; petals much smaller, dark purplish-brown. 

 DISTUIB. Europe (Arctic), except Turkey, all N. Asia, E. and W. N. 

 America. Rootstock powerfully astringent, and yields a yellow dye. 

 SECTION 3. Sibbald'ia, L. (gen.). Petals 5-7, linear-oblong or 



(yellow in the British species). Stamens 4-10. Achenes 4-10, glabrous, 



on a concave pubescent receptacle. 



3. P. procum'bens, Clairv. ; leaves 3-foliolate, leaflets obovate trun- 

 cate and 3-5-toothed at the tip. Sibbaldia procumbens, L. 



Stony places on the Scotch alps, from Peebles northward, between 1,500 and 

 4,000 ft. ; fl. July. More or less hairy and glaucous. Rootstock woody, 

 depressed, branches leafy at the tip. Leaves 1-3 in. ; leaflets -1 in. Flower- 

 inif .-items 3-5 in., lateral, ascending, leafy. Flowers J in. diam., few, in 

 terminal close cymes. Petals small. Calyx-seyments lanceolate, acute ; 

 bracteoles linear. DISTRIB. Alpine and Arctic Europe, Asia from the 

 Himalaya northwards, N. America. 

 SECTION 4. Potentil'la proper. Petals 5, rarely 4, orbicular or obcor- 



date, usually yellow or white. Stamens many. Achenes many, glabrous 



or nearly so, on a concave glabrous or hairy receptacle. 



* Flowering stems annual, from below the crown of the rootstock. 



4. P. Tormentil'la, Sibthorp ; stem slender rarely rooting, leaves 3- 

 rarely 5-lbliolate, flowers usually cymose, petals usually 4 yellow, acheues 

 reticulate. Torment-ilia o/icina'lis, Curtis. 



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