ROSE FAMILY 123 



straightish prickles below. Leaves petioled, of 3-7 ovate leaflets which 

 are acute, irregularly serrate, soft-hairy beneath. Flowers racenied, 

 the lower ones leafy-bracted. Petals white, obovate, much longer 

 than the taper-pointed sepals. Fruit long, of small drupelets. Common 

 in thickets.* 



6. R. cuneifolius Pursh. Sand Blackbp:rry. Stem shrubby, 

 erect or diffuse, 2-3 ft. high ; prickles straight or recurved. Leaves 

 petioled, 3-5 -foliate ; leaflets obovate, serrate towards the apex, 

 wedge-shaped towards the base, rough above, white downy-woolly 

 beneath. Racemes mainly terminal, few-flowered. Petals white, 

 longer than the sepals. Fruit ovoid, black, smaller than the preced- 

 ing. Common in old fields.* 



7. R. hispidus L. Running Swamp Blackberry. Stem trailing 

 or prostrate, often several feet in length, armed with recurved 

 prickles. Leaves petioled, mostly of 3 leaflets; leaflets obovate, 

 obtuse, thick, dark green and shining above. Flowering branches 

 commonly erect, few-flowered, flowers white. Fruit small, reddish, 

 turning nearly black. In swamps and low ground. 



8. R. villosus Ait. Low Blackberry, Dewberry. Stems 

 shrubby, trailing w^idely, 3-10 ft. long, somewhat prickly. Leaflets 

 usually 3, but sometimes 5 or 7, ovate, acute, sharply (and doubly) 

 cut-serrate, thin. Racemes upright on the short branches, 1-3-flow- 

 ered. Fruit roundish, of fewer and larger grains than Xo. 5, very 

 sweet when fully ripe. Common N., in stony or gravelly fields. 



XIII. ROSA L. 



Erect running or climbing prickly shrubs. Leaves pinnate, 

 leaflets serrate, stipules united to the petiole. Calyx tube urn- 

 shaped, with a rather narrow mouth. Petals (in single roses) 5. 

 Stamens many, inserted around the inside of the mouth of the 

 calyx tube. ()varies many, hairy, ripening into bony akenes, 

 inclosed in the rather fleshy and sometimes eatable calyx tube. 



1. R. pratincola Greene. Stems densely prickly, 1-2 ft. high. 

 Stipules narrow, usually with glandular teeth or a fringe of glandu- 

 lar hairs toward the tip; leaflets 7-11, varying from elliptical to 

 nearly obovate, obtuse at the tip, narrowed at the base, simply 

 toothed or serrate, rather firm and distinctly veined. Flowers usually 

 in corymbs ; sepals lanceolate, taper-pointed. Fruit globose, smooth. 

 Prairies, especially W. 



2. R. blanda Ait. Early Wild Rose. Stems 1-3 ft. high, usually 

 without prickles; sti})ules broad. Flowers generally large, corynibed 

 or solitary; sepals after flowering closing over the mouth of the calyx 

 tube and persistent. Rocks and rocky shores. 



