Stems 0.5-2(-3) m, mostly erect or nearly so, the young primocanes often sparsely glandular; primocane lvs softly pubescent beneath; terminal lfl typically ovate-oblong, varying to ovate, 1-2 dm, widest near or below the middle, long-acuminate, finely and sharply serrate, rounded to truncate or subcordate at base; lateral lfls usually 4, smaller; armature of the stem of nearly straight prickles spreading at right angles or barely reflexed, much flattened at the long base; prickles of the petioles, pedicels, and midveins similar but prominently hooked; infl racemiform, commonly elongate and many-fld, the lower 1 or 2(3) fls subtended by lvs, the others by stipules only; pedicels tomentose and glandular; fls 2 cm wide; sep acute to more commonly short-caudate; pet cuneate and separate at base. Our commonest tall blackberry, occurring in a wide variety of mostly disturbed habitats, from N.S. and Que. to Minn., s. almost throughout our range and along the mts. to N.C. and Tenn. May-July. (R. abbrevians; R. alumnus; R. attractus; R. concameratus; R. flavinanus; R. frondisentis; R. inclinis; R. nuperus; R. ortivus; R. paulus; R. perinvisus; R. pugnax; R. reravus; R. saltuensis)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.
Stems usually stout, 1-3 m; armature of the primocanes of straight, spreading, or slightly reflexed prickles from an expanded base; shorter hooked prickles usually present on the petioles, often on the petiolules, and occasionally on the midveins and on the axis of the raceme, rarely in much weaker form on the pedicels; primocane lvs softly pubescent beneath, 3- or 5-foliolate; terminal lfl broadly ovate, 6-12 cm, half to nine-tenths as wide, broadest near or above to often well below the middle, distinctly acuminate, broadly rounded or subcordate at base, very coarsely and irregularly serrate to doubly serrate; floricane lvs usually with elliptic to rhombic or obovate lfls coarsely toothed above the middle, many of them simple and broadly ovate or subrotund; raceme usually short and compact, few-fld, well surpassing the lvs, varying to loose and open with long-pedicellate fls. Me. and N.H. to Minn., s. to Va., W.Va., Ind., and Mo. May-July. (R. acer; R. amnicola; R. associus; R. avipes; R. barbarus; R. bellobatus; R. bractealis; R. brainerdii; R. bushii; R. cardianus; R. condensiflorus; R. congruus; R. cupressorum; R. defectionis; R. dissitiflorus; R. facetus; R. floricomus; R. floridus; R. frondosus; R. independens; R. insulanus; R. latifoliolus; R. libratus; R. multispinus; R. ostryifolius; R. pauxillus; R. perfoliosus; R. philadelphicus; R. praepes; R. pratensis; R. recurvans; R. subsolanus; R. wisconsinensis)
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.