124 ROSACE^E. [POTENTILLA. 



bark flaking. Leaves oblong or lanceolate ; leaflets 3-5, g-f in. ; margins 

 entire, revolute; stipules entire. Flowers 1-1| in., few, in terminal sub- 

 corymbose cymes, golden yellow, sub-1-sexual, homogamous; bracteoles 

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

 Europe, Alps (Arctic), N. and W. Asia, Himalaya, N. America. In Tees- 

 dale the flowers appear to be functionally 1 -sexual ; the sexes differ in 

 appearance. 



SECTION 2. Co'marum, L. (gen.). Petals 5, small, purple-brown. 

 Stamens many. Achenes many, glabrous, on a conical dry spongy dowuy 

 receptacle. 



2. P. Co'marum, Nestl. ; leaves pinnately 5-7-foliolate. Co'marum 

 palustra, L. 



Bogs and marshes, ascends to 2,800 ft. in the Highlands ; Ireland ; Channel 

 Islands; fl. June-July. Sparingly hairy. Rootstock long, woody; roots 

 fibrous. Stems i-lg ft., ascending, purple-brown. Leaves 2-4 in. ; leaflets 

 lJj-2 in., narrow-oblong, obtuse, coarsely serrate, pale beneath ; stipules 

 large, membranous, free portion often cut. Flowers 1-1^ in. diam., few. 

 Bracteoles smaller than the ovate-lanceolate acuminate sepals, purplish. 

 Petals much smaller, dark purplish-brown. DISTRIB. Europe (Arctic), 

 N. Asia, N. America. Rootstock powerfully astringent, and yields a 

 yellow dye. 



SECTION 3. Sibbald'ia, L. (gen.). Petals 5-7. Stamens 4-10. 

 Achenes 4-10, glabrous, on a concave pubescent receptacle. 



3. P. Sib'baldi, Hall. f. ; leaves 3-foliolate, leaflets obovate truncate 

 tip 3-6 -toothed. P. procum'bens, Clairv. ; Sibbald'ia procum'bens, L. 

 Stony places on the Scotch alps, from Peebles north to Shetland ; alt. 1,500- 



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. 

 Flowering stems 3-5 in., axillary, ascending, leafy. Flowers J in. diam., 

 few, in terminal close cymes. Petals small, narrow, orange-yellow, or 0. 

 Calyx-segments lanceolate, acute ; bracteoles linear. DISTRIB. Alpine and 

 Arctic Europe, N. Asia, Himalaya, N. America. 



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

 date, usually yellow or white. Stamens many. Achencs many, on a 

 concave glabrous or hairy receptacle. 



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



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

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

 reticulate. 



Heaths, copses, dry pastures, N. to Shetland ; ascends to 3,300 ft. in the 

 Highlands; Ireland; Channel Islands; fl. June-Sept. Slightly hairy. 

 Rootstock stout, almost tuberous. Stems 6-10 in., slender, leafy, clothed 

 with curly hairs. Leaves subsessile ; radical petioled, leaflets - in., obovate- 

 cuneate, tip 3-4-toothed or -lobed ; cauline subsessile, leaflets much narrower; 

 stipules foliaceous, cut. Flowers |-| in. diam., yellow, homogamous. Calyx- 



