516 



ROSACEAE 



Fruit falling away from the dry receptacle : petals erect. (Raspberries. ) 



Stems prickly, glaucous : fruit purple-black or black. 1. R. occidentalis 



Stems bristly, not glaucous : fruit light red. 2. R. strigosus 



Fruit persistent on a fleshy receptacle : petals spreading. (Blackberries.) 

 Stems erect, ascending or recurved. 



Leaf-blades white- woolly beneath. 3. jj cuncifolius 



Leaf-blades not white-woolly beneath. 



Branches of the inflorescence and the petioles distinctly glandular-pu- 

 bescent. 



Fruit broadly oval or nearly spherical, very juicy. 4. R. nigrobaccus 



Fruit narrowly oblong or thimble-shaped, comparatively dry. 5. R. Allegheniensis 



Branches of the inflorescence and petioles villous, strigose or nearly 



glabrous, scarcely glandular. 

 Pubescence copious in the inflorescence. 



Terminal leaflet % longer than the lateral ones, oblong or oblong- 

 ovate. 6. R. ostryifoliut. 

 Terminal leaflet slightly longer than the lateral ones, obovate to 



rhombic. 

 Prickles of the stem flattened only at the base, straight or slightly 



curved. 7. R.frondotus 



Prickles of the stem much flattened throughout, strongly hooked. 8. R. floridut. 

 Pubescence sparse in the inflorescence. 



Plants low, almost herbaceous, weakly prickly. 9. R. Randii. 



Plants tall and shrubby. 

 Plants strongly prickly. 



Leaflets pubescent beneath, doubly serrate. 10. R. argutus. 



Leaflets glabrous beneath, singly serrate. 11. R. beiulifoliut. 



Plants unarmed or with few weak prickles. 12. R. Canadtnsit. 



Stems trailing, creeping or decumbent. 



Leaflets thin, membranous : leaves deciduous. 

 Stems merely prickly. 



Inflorescence usually several-many-flowered. 



Corolla generally over 3 cm. broad : inflorescence usually glandu- 



liferous : terminal leaflets of the shoots rounded at the base. 

 Leaflets simply serrate. 13. R. invisus. 



Leaflets doubly serrate. 14. R. roribaccut. 



Corolla generally less than 3 cm. broad : inflorescence not glandu- 

 liferous : terminal leaflets of the shoots cuneate or obtuse at 

 the base. 



Terminal leaflet % longer than the lateral ones, oblong or oblong- 

 ovate, acute. 6. R. ostryijoliut. 

 Terminal leaflet slightly longer than the lateral ones, ovate, acu- 

 minate. 

 Leaflets mostly acute or acuminate, glabrous or somewhat 



pubescent beneath : peduncles slightly villous. 15. R. procumbent. 



Leaflets mostly obtuse, tomentulose beneath : peduncles 



densely tomentulose or tomentose. 16. R. rhodophyUun. 



Inflorescence usually 1-2-flowered. 



Lateral leaflets cuneate at the base, glabrous. 



Leaflets sharply serrate with triangular teeth. 17. R. subuniflorua. 



Leaflets crenate-serrate with ovate teeth. 18. R. Emleiiii. 



Lateral leaflets rounded at the base, pubescent beneath. 19. R. Baileyanua. 



Stems bristly and prickly, sometimes merely bristly. 



Flowering branches and petioles bristly or glabrous : terminal leaflets^ 



cuneate. 20. R. hispidus. 



Flowering branches and petioles prickly : terminal leaflets oblong-el- 

 liptic. 21. R..carpinifoliu8. 

 Leaflets leathery : leaves persistent, evergreen. 



Corolla 1-1.5 cm. broad. 20. R. hispidus. 



Corolla 2-3.5 cm. broad. 



Flowering branches usually simple and 1-flowered. 22. R. trivialis. 



Flowering branches usually corymbosely branched and several-flow- 

 ered. 

 Pedicels not bristly under The hypanthium : stems with recurved 



prickles. 23. R. persistens. 



Pedicels densely bristly under the hypanthium : stems with straight 



prickles and numerous bristles. 24. R. rubrisetus. 



1. Rubus occidentals L. A straggling shrub, with cane-like glaucous prickle- 

 armed branches 1-3 m. long, curved, sometimes rooting at the end. Leaves pinnately 3- 

 foliolate, or rarely 5-foliolate : blades of the leaflets ovate to obovate, 2-8 cm. long, acute 

 or acuminate, incised-serrate, sometimes lobed, cuneate or subcordate at the base : flowers 

 not showy, in terminal corymbs : sepals oblong-ovate or ovate-lanceolate, 5-6 mm. long, 

 acuminate : petals white, spatulate or cuneate-spatulate, 4-5 mm. long, obtuse : fruit de- 

 pressed-hemispheric, black or purple-black, 8-12 mm. broad. 



On the borders of woods and in rocky thickets, Quebec to Ontario, northern Georgia, Alabama 

 and Missouri. Spring. BLACK RASPBERRY. BLACK-CAP. 



2. Rubus strigosus Michx. A branching shrub, 1-2 m. tall, with curved branches 

 and more or less densely bristly foliage. Leaves pinnately 3-5-foliolate : blades of the 

 leaflets ovate to oblong-ovate or ovate-lanceolate, rarely elliptic, 2-8 cm. long, acute or 

 acuminate, slightly serrate, sometimes slightly lobed, glabrous above or nearly so, white- 

 tomentose beneath, usually rounded at the base : flowers in loose racemes or panicles : 





