THE SMALL FRUITS OF NEW YORK 55 



DEWBERRIES AND BLACKBERRIES 



This subgenus inhabits the temperate regions of northwestern Asia, 

 Europe, northern Africa, North America, and along the mountains in South 

 America. It is abundantly rich in individuals and forms in Europe and 

 northeastern America. This subgenus presents the greatest difficulties to 

 the botanist. The various species with their numerous satelites, variously 

 considered as subspecies, microspecies, varieties, forms, and hybrids, can be 

 grouped in a number of series, which, if once understood, are in most cases 

 readily distinguished. It must not be forgotten, however, that the many 

 individual variations and the intermediate hybrid forms make it difficult to 

 work out tmder each of these series satisfactory keys. 



A. Plants with creeping or prostrate canes. Leaves often 3-foliolate. Inflorescence 

 usually few flowered or flowers at least never panicled (Dewberries) 

 B. Plants more prickly, prickles sometimes mixed with bristles 

 C. Canes glaucous with a bloom 



D. Flowers bisexual, with perfect stamens and pistils. Berries rarely perfect, 

 usually only a few drupelets maturing, the others abortive. European- 

 Asiatic species Series r : Caesii 



DD. Flowers usually with one sex only perfect. Berries always perfect, composed 



of many drupelets. Pacific species. Califomian Dewberries 



Series 2: Ursini 

 CC. Canes not glaucous 



D. Canes with broad, more or less ovate leaflets, without bristles. Foliage 



deciduous (Northeastern Dewberries) Series 3 : Flagellares 



DD. Canes with narrower, more lanceolate leaflets, and often with bristles between 



the prickles. Foliage often persistent (Southeastern Dewberries) 



Series 4: Triviales 



BB. Plants with numerous fine retrorse bristles and a few prickles or none 



Series 5 : Hispidi 

 AA. Plants with more or less erect canes, often tall, nodding or arching at the top, some- 

 times more so the second year, but not really prostrate, more or less angular. 

 Leaves mostly digitately or pedately s-foliolate. Inflorescence more or less 

 panicled (Blackberries) 

 B. Plants with setose bristles on canes and petioles; canes often decumbent or 



prostrate the second year Series 6 : Setosi 



BB. Plants not setose in the same way 



C. Leaves white or grayish tomentose underneath 



D. Leaves more or less oblong or even narrower. American plants 



Series 7 : CtineifoUi 

 DD. Leaves more or less ovate or roundish. European plants. . Series 13 : Fruticosi 

 CC. Leaves more or less green underneath 



D. Canes unarmed or only with a few prickles; plants almost glabrous and not 



glandular; leaves thin Series 8: Canadenses 



DD. Canes armed with more or less stout prickles; plants mostly more or less 

 pubescent 



