Rubus trivialis
Rubus pascuus
southern dewberry
Chesapeake blackberry, Nanticoke blackberry, topsy
biennial, initially low-arching, then falling and creeping (or climbing through other vegetation), glabrous or moderately hairy, sparsely to densely short- to long-stipitate-glandular, not pruinose;
prickles moderate to dense, recurved, sometimes distally slender, 1–4 mm, broad-based;
bristles absent or sparse to dense, erect to retrorse, red to purple, rarely green, slender, weak, gland-tipped.
biennial, arching, sparsely to densely hairy, sparsely to densely sessile-glandular, rarely short-stipitate-glandular, not pruinose;
bark not papery, peeling;
prickles moderate to dense, hooked, retrorse, or erect, stout, 4–10 mm, broad- or narrow-based.
persistent or semipersistent, ternate to palmately compound, lustrous;
stipules filiform, linear, or lanceolate, 2–12(–15) mm;
leaflets 3–5, terminal narrowly elliptic or ovate to obovate, 2–8.5 × 0.7–4.5 cm, base rounded to cuneate, unlobed, margins moderately to coarsely serrate to doubly serrate, apex acute to acuminate, abaxial surfaces with hooked prickles on midvein, glabrous or sparsely to moderately hairy, eglandular or sparsely short-stipitate-glandular along central vein.
deciduous to semievergreen, palmately compound, rarely ternate;
stipules filiform to linear, rarely narrowly lanceolate, 5–16(–20) mm;
leaflets 3–5, terminal broadly elliptic or ovate, (3.5–)4.5–8.5 × 2.5–6 cm, base rounded, unlobed, margins moderately to coarsely doubly, rarely singly, serrate, apex acute or short-acuminate, abaxial surfaces with hooked prickles on larger veins, short-velutinous to tomentose, sparsely to densely sessile-glandular, rarely short-stipitate-glandular.
terminal on short shoots, usually appearing axillary, 1(–3)-flowered.
terminal and axillary, 3–15(–25)-flowered, cymiform to thyrsiform, not projected well beyond subtending leaves.
prickles and, often, bristles moderate to dense, recurved, moderately to densely hairy, sparsely to moderately sessile- to short-stipitate-glandular.
prickles moderate to dense, hooked, retrorse, or erect, densely hairy, eglandular or sparsely to moderately sessile-glandular.
bisexual;
petals white to pink, elliptic to obovate, 10–16(–25) mm;
filaments filiform;
ovaries glabrous.
bisexual;
petals white to pale pink, obovate or elliptic to orbiculate, (8–)10–15 mm;
filaments filiform;
ovaries glabrous or apically hairy.
black, globose to ovoid, 1–1.5(–2) cm;
drupelets 10–50, strongly coherent, separating with torus attached.
black, globose to subcylindric, 1–2 cm;
drupelets (15–)20–40(–50), strongly coherent, separating with torus attached.
= 14.
= 21, 28.
Rubus trivialis
Rubus pascuus
Rubus trivialis is distinguished from other species of Rubus by its frequently glandular-bristly and generally creeping stems, abundant recurved prickles, and typically persistent or semipersistent, lustrous primocane leaves with relatively narrow leaflets. Although emerging primocanes typically reach to 30 cm above the ground, vigorous plants can have new primocanes standing erect to 70 cm that later fall to the ground or onto adjacent vegetation as they continue to enlarge. L. H. Bailey (1941–1945) believed that there was no clear separation between members of sect. Persistentes Fernald (referred to by Bailey as sect. Verotriviales [illegitimate sectional name for R. trivialis and associated species]) and sect. Procumbentes (by Bailey as sect. Flagellares; including R. flagellaris and related species). All characteristics that he recognized for distinguishing sect. Persistentes from sect. Procumbentes are often present in the latter, with the exception of hispid-setose stems, and glabrous plants of R. trivialis are difficult to distinguish from some plants of R. flagellaris; to include the latter species within the former would be reasonable.
Rubus ×inferior L. H. Bailey is a putative hybrid of R. trivialis and R. cuneifolius.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Rubus pascuus is probably more widespread than indicated here. The species is most likely to be mistaken for R. bifrons, R. cuneifolius, or R. pensilvanicus. Unlike R. bifrons, R. pascuus is generally more densely glandular, has much shorter, compact inflorescences that usually barely surpass the leaves, and tends to hold its primocane leaves relatively erect (versus spreading in R. bifrons). Although both can be semievergreen, R. pascuus will lose its leaves more readily than R. bifrons in areas where they co-occur. When compared with R. cuneifolius, R. pascuus has pale pink to white petals and ovate to broadly elliptic leaflets with flat margins, the entire part restricted to the base; R. cuneifolius has white petals and cuneate to obovate leaflets with usually revolute margins, the proximal third entire. When compared with R. pensilvanicus, R. pascuus has pale pink to white petals. Rubus pensilvanicus only has white petals as well as abaxial leaf surfaces, which are white to gray-green in R. pascuus with dense, short-velutinous to tomentose indument, while those of R. pensilvanicus can be hairy but never whitish to gray-green. A notable aspect of R. pascuus is how vigorously armed it is, more so than most other Rubus species in the flora area.
Rubus pascuus may represent a stabilized hybrid between a European and a native blackberry species, suggested by whitish pubescence on the abaxial leaf surface and pale pink petals. L. H. Bailey placed R. pascuus in his sect. Cuneifolii (L. H. Bailey) L. H. Bailey, likely because of the whitish hairs on the abaxial leaf surface.
The use of the name Rubus pascuus here is tentative; it is the best fit to the material observed. This treatment follows H. A. Davis (1990) for the choice of the name to use and its associated synonymy.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
IL Wildflowers
KS Wildflowers
LA Plants
MO Plants
WildflowerSearch
iNaturalist
USDA Plants Database
MD Biodiversity
