Rubus cuneifolius
Rubus canadensis
sand blackberry
Canadian or smooth highbush blackberry, ronce du Canada, smooth blackberry
biennial, erect, rarely arching, sparsely to densely hairy (especially young), eglandular, not pruinose;
bark not papery, peeling;
prickles usually dense, hooked to retrorse, usually stout, 3–6 mm, broad-based.
biennial, arching, glabrous, eglandular or sparsely sessile- to short-stipitate-glandular, not pruinose;
prickles absent or sparse, erect or slightly retrorse, slender, 2–5 mm, narrow- to broad-based.
deciduous to semievergreen, usually ternate, sometimes palmately compound;
stipules filiform or linear to lanceolate, 3–15 mm;
leaflets 3–5, terminal cuneate to obovate, 2–6 × 3–4 cm, base cuneate, unlobed, margins serrate, rarely doubly serrate, apex broadly rounded to subtruncate, often cuspidate, abaxial surfaces often with prickles on midveins, densely gray- to white-hairy, sparsely to densely sessile-glandular.
deciduous, usually palmately compound, lustrous;
stipules filiform to narrowly lanceolate, (5–)8–15(–22) mm;
leaflets (3–)5, terminal ovate to elliptic, (3–)7–9(–11) × (3–)4–5(–6) cm, base rounded to shallowly cordate, unlobed, margins finely to coarsely serrate or doubly serrate, apex acuminate to attenuate, abaxial surfaces sometimes with hooked prickles on midvein, glabrous or puberulent, eglandular.
terminal on short shoots, sometimes appearing axillary, (1–)3–5(–12)-flowered, cymiform.
terminal on short shoots, sometimes appearing axillary, (5–)15–25-flowered, racemiform.
unarmed or prickles sparse to moderate, hooked to retrorse, moderately to densely hairy, eglandular or sparsely to moderately sessile-glandular.
usually unarmed, hairy, eglandular or sparsely sessile- to short-stipitate-glandular.
bisexual;
petals white, elliptic to obovate, 5–15 mm;
filaments filiform;
ovaries glabrous or glabrate.
bisexual;
petals white, obovate to elliptic, 8–22 mm;
filaments filiform;
ovaries glabrous.
black, globose to cylindric, 0.6–2 cm;
drupelets 15–50, strongly coherent, separating with torus attached.
black, globose to short-cylindric, 1–2 cm;
drupelets 10–75, strongly coherent, separating with torus attached.
= 21, 28.
= 14, 21.
Rubus cuneifolius
Rubus canadensis
Rubus cuneifolius is characteristic of the Coastal Plain and Piedmont. The species is distinguished from most other blackberries in the flora area by its usually strongly erect and shrub-forming habit and abaxial leaflet surfaces often with dense white to gray indument; it may be confused with R. pascuus. Rubus cuneifolius has white petals and cuneate to obovate leaflets with usually revolute margins, the proximal third entire; R. pascuus has pale pink to white petals and ovate to broadly elliptic leaflets with the margins flat and entire only at base.
Rubus longii Fernald may represent hybridization between R. cuneifolius and another, yet-undetermined, blackberry (perhaps R. pascuus). Hybrids of R. cuneifolius and R. hispidus can be found around abandoned commercial cranberry bogs in New Jersey (G. Moore, pers. obs.). Rubus cuneifolius is introduced in South Africa and is officially recognized there as a noxious weed (L. Henderson 1995; T. Olkers and M. P. Hill 1999; H. Klein 2002). Preliminary examination of plants identified as R. cuneifolius from South Africa has shown that the plants are not R. cuneifolius but may be hybrids involving R. cuneifolius and another species.
The following nothospecies names are based on putative hybrids involving Rubus cuneifolius and: R. pensilvanicus (R. ×acer L. H. Bailey, R. ×acer var. subacer L. H. Bailey, R. ×argutinus L. H. Bailey, R. ×floridensis L. H. Bailey); R. trivialis (R. ×inferior L. H. Bailey).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Rubus canadensis has a wide range and is the most northerly of all the highbush blackberries. The species is morphologically similar to R. allegheniensis except that the plants have little armature, are not as hairy, and have no glands. It also has characteristically lustrous leaves. The open and edge habitats in which it grows can greatly influence the phenotype, as with most highbush blackberries. At higher elevations or in poorer soil conditions, the plants are smaller; when partially shaded, leaves of primocanes may be larger. Leaves of floricanes vary in size and shape and are unreliable for identification. Because of the variation, multiple names have been erected, especially locally; it is felt that a stricter approach to defining it is prudent. Some of the names traditionally associated with sect. Canadenses (L. H. Bailey) L. H. Bailey are here associated with other Rubus species or are considered to refer to putative hybrids.
The following nothospecies names are based on putative hybrids involving Rubus canadensis and: R. allegheniensis (R. ×forestalis L. H. Bailey, R. ×immanis Ashe); R. flagellaris (R. ×lepagei L. H. Bailey, R. ×rixosus L. H. Bailey); R. hispidus (R. ×novanglicus L. H. Bailey); R. pensilvanicus (R. ×amabilis Blanchard [not Focke], R. ×amicalis Blanchard, R. ×elegantulus Blanchard [= R. canadensis var. elegantulus (Blanchard) Farwell], R. ×multilicius L. H. Bailey, R. ×noveboracus L. H. Bailey, R. ×pergratus Blanchard [= R. canadensis var. pergratus (Blanchard) L. H. Bailey], R. ×crux Ashe); R. setosus (R. ×miscix L. H. Bailey [based on R. ×peculiaris Blanchard (not R. peculiaris Sampaio)]).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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