222 SYSTEMATIC BOTANY. 



purple, nodding ; petals purplish-yellow, broad obovate. In bogs and wat 

 meadows. June. 



6. Potentilla. Calyx 4-5-cleft, with 4-5 alternate, exterior seg- 

 ments. Petals 4-5, dentate, deciduous. Stamens numerous, with slen- 

 der filaments. Ovaries numerous, in a head, on a dry receptacle. 

 Styles deciduous. Achenia numerous, if 



1. P. CANADENSIS (Five-finger}. Hirsute-pubescent; procumbent; leaves 

 palmately 3-5-foliate ; leaflets obovate, silky beneath ; stipules 2-3-cleft, or 

 entire ; flowers yellow, on axillary, solitary pedicels. A very common and 

 variable species, sporting into apparently distinct varieties under the influ- 

 ence of different soils. April-August. 



Var. PUMILA. Very small and delicate. In dry soils. April-May. 



2. P. ARGENTEA {Silvery Cinquefoil). Stems ascending, hoary-tomen- 

 tose ; leaves palmately 3-5-foliate ; leaflets oblong, incised, entire at base, 

 with a revolute margin, silvery beneath ; flowers small, yellow, in crowded 

 corymbs ; petals longer than the canescent sepals. June-September. 



7. Fragaria. Calyx concave, deeply 5-cleft. Petals 5, obcordate. 

 Stamens numerous. Achenia dry, smooth, scattered on the enlarged, 

 pulpy, deciduous receptacle. Leaves trifoliate. Stems stolonifer- 



OUS. 2f 



1. F. VIRGINIANA (Field Strawberry}. Plants pubescent ; leaflets oval, 

 coarsely serrate ; flowers white, on few-flowered scapes ; fruit roundish-ovoid ; 

 achenia imbedded in pits on the receptacle ; calyx spreading in fruit. A well- 

 known plant, in fields and meadows, universally a favorite for its delicious 

 fruit. April-May. 



2. F. VESCA (English Strawberry], Plant pubescent, leaflets oval, coarse- 

 ly serrate, or dentate ; flowers white, on scapes longer than the leaves ; 

 achenia scattered in the surface of the conical or semi-spherical fruit, which 

 is not pitted. Common in cultivation. April-May. 



8. Waldsteinia. Calyx 5-cleft, with 5 alternate bracteoles. 

 Petals sessile, deciduous. Stamens numerous, inserted into the calyx. 

 Achenia few, dry, on a short receptacle, y. 



W. FRAGARIOIDES (Dry Strawberry). Leaves trifoliate, with pubescent 

 petioles ; leaflets crenately toothed, and incised ; scapes many-flowered ; flow- 

 ers yellow ; petals obovate. In shady and hilly woods. June. 



9. Rubus. Calyx 5-parted, spreading. Petals 5, deciduous. Sta- 

 mens numerous. Ovaries numerous, with 2 ovules. Achenia pulpy, 

 aggregated on a conical, juicy receptacle. Receptacle deciduous, y. 



1. R. VILLOSUS (High Blackberry]. Stem mostly erect, angular, armed 

 with stout, curved prickles ; young branches and peduncles villous and gland- 

 ular ; leaves palmately 3-5-foliate ; leaflets ovate ; flowers white, in leafless 

 racemes of 20-25. Fruit oblong, large, black, sweet and delicious. 



2. R. HISPIDUS (Bristly Blackberry}. Stem slender, prostrate, clothed 



