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southern dewberry

European blackberry, Himalayan berry, Himalayan blackberry, twice-leaf blackberry

Habit Shrubs, to 3(–7) dm, sometimes climbing higher through other vegetation, moderately to densely armed. Shrubs, (3–)10–50 dm, armed.
Stems

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, sometimes creeping early or with age, sparsely to densely hairy, eglandular or sparsely sessile-glandular, not or weakly pruinose;

prickles moderately dense, hooked, retrorse, or erect, stout, 4–10 mm, broad- or narrow-based.

Leaves

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;

stipules filiform to linear, 7–15 mm;

leaflets 3–5, terminal elliptic or ovate to suborbiculate, 6–15 × 4–9 cm, base rounded to shallowly cordate, unlobed, margins moderately to coarsely serrate, apex acute or acuminate to short-attenuate, abaxial surfaces white (gray-green in shade), with hooked prickles on largest veins, short-velutinous to tomentose, eglandular, rarely sparsely sessile-glandular along midveins.

Inflorescences

terminal on short shoots, usually appearing axillary, 1(–3)-flowered.

terminal, sometimes also axillary, 10–60(–100)-flowered, thyrsiform, projected well beyond subtending leaves.

Pedicels

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 to retrorse or erect, densely hairy, eglandular or sparsely to moderately sessile-glandular.

Flowers

bisexual;

petals white to pink, elliptic to obovate, 10–16(–25) mm;

filaments filiform;

ovaries glabrous.

bisexual;

petals white to pink, obovate or elliptic to orbiculate, 10–15 mm;

filaments filiform;

ovaries apically hairy.

Fruits

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 15–40(–50), strongly coherent, separating with torus attached.

2n

= 14.

= 28, 48.

Rubus trivialis

Rubus bifrons

Phenology Flowering Jan–Jun. Flowering (Apr–)May–Aug(–Sep).
Habitat Open woodlands, savannas, prairies, meadows, sand dunes, disturbed areas, dry to seasonally wet soil Woodland edges, dry or mixed woods, open areas, often disturbed, roadsides, moist soil
Elevation 0–200 m (0–700 ft) 0–1200(–1800) m (0–3900(–5900) ft)
Distribution
from FNA
AL; AR; FL; GA; IL; KS; KY; LA; MO; MS; NC; OK; SC; TN; TX; VA; Mexico (Coahuila, Nuevo León, Tamaulipas)
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AL; AR; AZ; CA; CO; CT; DC; GA; ID; IL; KS; KY; LA; MA; MD; MO; MS; MT; NC; NJ; NM; NV; NY; OH; OK; OR; PA; RI; SC; TN; TX; UT; VA; WA; BC; ON; Europe [Introduced in North America]
[WildflowerSearch map]
[BONAP county map]
Discussion

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 bifrons lacks the strongly pruinose stems of the related R. ulmifolius and has usually much larger leaves. The species also often has much broader inflorescences than R. ulmifolius or the related R. vestitus. It is less densely glandular and has longer and more open inflorescences than R. pascuus, and unlike the latter it has spreading, not erect, primocane leaves. Rubus bifrons also lacks the stipitate-glandular hairs and nearly round primocane terminal leaflets of R. vestitus; seedlings of R. bifrons can be densely stipitate-glandular.

L. H. Bailey (1941–1945), M. L. Fernald (1950), Y. Heslop-Harrison (1968), and H. A. Gleason and A. Cronquist (1991) distinguished between Rubus bifrons and another species (referred to as either R. discolor or R. procerus P. J. Müller ex Boulay, both often considered synonyms of R. armeniacus), based on stem shape and indument, prickle shape and angle, leaf shape and margins, inflorescence shape, and petal color. Plants in North America identified as either R. bifrons or the other species can vary broadly in any of these characters, even within individual stems, making it extremely difficult or impossible to distinguish between these species in the flora area. Recent research addressing the genetics or species distinctiveness in this complex in Europe (J. Kollmann et al. 2000) and Australia (K. J. Evans et al. 2007) did not sample plants from North America, and recent work within the flora area (L. V. Clark et al. 2013) addressed this complex only in California, Oregon, and Washington. Until a much-needed genetic study is performed that includes a broad selection of plants of ser. Discolores from throughout North America, Europe, and elsewhere, the precise identities of all of our material in this complex will be elusive. With this degree of uncertainty, a conservative approach is taken here, which is consistent with the treatment herein of the native blackberries. The results of more comprehensive DNA research may show that a different name than R. bifrons is to be used in the flora area. The name R. discolor often has been misattributed as a synonym of R. armeniacus; it is a synonym of R. ulmifolius (H. E. Weber 1985).

In the flora area, Rubus bifrons is most abundant from northern California northward to British Columbia, where it can grow in great density over large areas, often to the exclusion of all other vegetation (for example, K. Williams et al. 2006). There are reports of R. bifrons (as R. armeniacus or R. procerus) hybridizing with R. ursinus (T. S. Mallah 1954; L. V. Clark and M. Jasieniuk 2012; B. Sutherland and L. Alice, unpubl.) and R. laciniatus (R. K. Bammi and H. P. Olmo 1966).

Rubus thyrsoideus Wimmer is an illegitimate name that applies here.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 9, p. 54. FNA vol. 9, p. 36.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Rubeae > Rubus Rosaceae > subfam. Rosoideae > tribe Rubeae > Rubus
Sibling taxa
R. allegheniensis, R. arcticus, R. bartonianus, R. bifrons, R. caesius, R. canadensis, R. chamaemorus, R. cuneifolius, R. deliciosus, R. flagellaris, R. glaucifolius, R. hispidus, R. idaeus, R. illecebrosus, R. laciniatus, R. lasiococcus, R. leucodermis, R. neomexicanus, R. nivalis, R. niveus, R. nutkanus, R. occidentalis, R. odoratus, R. parviflorus, R. parvifolius, R. pascuus, R. pedatus, R. pensilvanicus, R. phoenicolasius, R. pubescens, R. repens, R. saxatilis, R. setosus, R. spectabilis, R. ulmifolius, R. ursinus, R. vestitus
R. allegheniensis, R. arcticus, R. bartonianus, R. caesius, R. canadensis, R. chamaemorus, R. cuneifolius, R. deliciosus, R. flagellaris, R. glaucifolius, R. hispidus, R. idaeus, R. illecebrosus, R. laciniatus, R. lasiococcus, R. leucodermis, R. neomexicanus, R. nivalis, R. niveus, R. nutkanus, R. occidentalis, R. odoratus, R. parviflorus, R. parvifolius, R. pascuus, R. pedatus, R. pensilvanicus, R. phoenicolasius, R. pubescens, R. repens, R. saxatilis, R. setosus, R. spectabilis, R. trivialis, R. ulmifolius, R. ursinus, R. vestitus
Synonyms R. agilis, R. continentalis, R. duplaris, R. ictus, R. lucidus, R. macvaughii, R. mirus, R. nessianus, R. riograndis, R. rubrisetus, R. sons, R. tallahasseanus R. armeniacus, R. linkianus
Name authority Michaux: Fl. Bor.-Amer. 1: 296. (1803) Vest: Steyermärk. Z. 3: 163. (1821)
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