Rubus allegheniensis
Rubus caesius
alleghaney blackberry, Alleghany blackberry, Allegheny blackberry, common blackberry, prairie rose, ronce des alléghanys, sow-teat berry
European dewberry
biennial, erect-arching, sparsely to densely hairy, sparsely to abundantly stipitate-glandular, glands usually flattened to cupulate, not pruinose;
prickles sparse to dense, erect or slightly retrorse, stout, 4–10 mm, broad-based.
biennial, creeping or arching then creeping, glabrous or hairy, eglandular or sparsely sessile- to short-stipitate-glandular, strongly pruinose;
prickles sparse to dense, erect to retrorse, slender, 1–3 mm, narrow- or broad-based.
deciduous, palmately compound, not lustrous;
stipules filiform to narrowly lanceolate, (2–)5–15(–20) mm;
leaflets (3–)5(–7), terminal ovate to lanceolate, 7–16 × 4–9 cm, base rounded to shallowly cordate, unlobed, margins finely to coarsely serrate or doubly serrate, apex acuminate to long-attenuate, abaxial surfaces with hooked prickles on midveins, moderately hairy, moderately to densely stipitate-glandular on veins.
deciduous, ternate;
stipules linear-lanceolate to ovate, 5–15 mm;
terminal leaflets ovate, 4–14 × 3–10 cm, base rounded to shallowly cordate, unlobed or shallowly lobed, margins coarsely serrate to doubly serrate, apex acute to acuminate, abaxial surfaces with prickles on midveins or unarmed, sparsely to moderately hairy, eglandular or sparsely short-stipitate-glandular along larger veins.
terminal on short shoots, sometimes appearing axillary, (5–)15–25-flowered, racemiform, often elongate.
terminal on short shoot, usually appearing axillary, 1–6-flowered, solitary flowers, cymiform, or racemiform.
unarmed or prickles sparse, hooked, densely hairy, densely short- to long-stipitate-glandular.
unarmed or prickles sparse to dense, erect to retrorse, densely hairy, sparsely to densely sessile- to short- or long-stipitate-glandular.
bisexual;
petals white, obovate to elliptic, rarely suborbiculate, 8–20 mm;
filaments filiform;
ovaries glabrous or glabrate.
bisexual;
petals white, obovate to elliptic or suborbiculate, 7–13 mm;
filaments filiform;
ovaries glabrous.
black, globose to cylindric, 1–2 cm;
drupelets 20–100, strongly coherent, separating with torus attached.
appearing bluish, black beneath bloom, pruinose, globose, 0.5–1.5 cm;
drupelets 1–5(–20), weakly coherent, separating with torus attached.
= 14, 21, 28.
= 28.
Rubus allegheniensis
Rubus caesius
Rubus allegheniensis consists of erect-arching, usually well-armed plants, usually densely stipitate-glandular with flattened to cupulate glands, particularly about the inflorescence.
The Menominee, Meskwaki, and Potawatomi used root extracts of Rubus allegheniensis to treat eye irritation (H. H. Smith 1923, 1928, 1933). The Ojibwa used boiled extracts of the canes as a diuretic and a root extract for treating diarrhea (Smith 1932). Rubus allegheniensis is introduced in British Columbia and California, where rare and in at least California probably no more than a waif.
Rubus montanus (Porter) Porter, a name that has been used for this species, is a later homonym of R. montanus Libert ex Lejeune.
The following nothospecies names are based on putative hybrids involving Rubus allegheniensis and: R. canadensis (R. ×forestalis L. H. Bailey, R. ×immanis Ashe); R. flagellaris (R. ×boyntonii Ashe, R. ×fraternalis L. H. Bailey [based on R. ×fraternus Brainerd & Peitersen (not R. fraternus Gremli), R. ×licens L. H. Bailey, R. ×ostryifolius Rydberg); R. pensilvanicus (R. ×avipes L. H. Bailey, R. ×floricomus Blanchard, R. ×orarius Blanchard); R. setosus (R. ×abbrevians Blanchard, R. ×aculiferus Fernald, R. ×adenocaulis Fernald, R. ×angustifoliatus L. H. Bailey, R. ×ascendens Blanchard, R. ×atwoodii L. H. Bailey, R. ×clausenii L. H. Bailey, R. ×flavinanus Blanchard, R. ×frondisentis Blanchard, R. ×perspicuus L. H. Bailey, R. ×ravus L. H. Bailey).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Within the flora area, Rubus caesius usually produces fruit with few, relatively large drupelets; in Eurasia, fruit with more drupelets are typical, and weakly pruinose fruit have been observed.
Rubus caesius is vegetatively similar to R. flagellaris and is introduced into parts of the geographic range of the latter; see M. P. Widrlechner (1998) for a comparison of these two species. Rubus caesius shows striking vegetative similarity to pruinose, trifoliate-leaved plants of R. ursinus, with which it may have a close relationship (L. A. Alice, unpubl.). In the absence of flowers or fruit, these two species could be mistaken for one another. Rubus caesius generally has broader middle primocane leaflets than R. ursinus, but that is not a consistent difference. Rubus caesius may have been introduced into the geographic range of R. ursinus; most herbarium specimens surveyed have been inadequate to make a proper determination. On specimen labels, herbarium collectors should describe at least the color of the fruit. In the last decade, R. caesius apparently has become much more aggressive around Ithaca, New York, despite occurring there since the early twentieth century (F. R. Wesley, pers. comm.).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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