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elm-leaf blackberry

bristly blackberry, bristly dewberry, ronce hispide, swamp dewberry

Habit Shrubs, 30–50 dm, unarmed or armed. Shrubs, sometimes herblike, to 2 dm, armed.
Stems

biennial, erect, then arching, usually moderately, rarely sparsely, hairy hairs stellate, eglandular, strongly pruinose;

prickles absent or sparse to dense, erect to hooked, stout, 3–10 mm, broad-based.

biennial, creeping, tip-rooting, flowering branches often erect, glabrous or sparsely hairy, sparsely to densely short- to long-stipitate-glandular, rarely eglandular, not pruinose;

prickles sparse to dense, erect to retrorse, weak, slender, 1–3(–5) mm, narrow-based;

bristles sparse to dense, erect or retrorse, narrow, flexible and weak, not gland-tipped.

Leaves

persistent or nearly so, ternate to palmately compound;

stipules filiform to linear, 4–12 mm;

leaflets 3–5, terminal ovate, elliptic, or suborbiculate to obovate, 4–10 × 2–6(–9) cm, base rounded to cuneate, unlobed, margins finely to moderately serrate, apex acute or acuminate to attenuate, abaxial surfaces with hooked prickles on larger veins, densely white short-velutinous, hairs usually minute, eglandular.

persistent, ternate or, rarely, palmately compound, lustrous;

stipules linear to narrowly lanceolate, (2–)5–15(–20) mm;

leaflets 3(–5), terminal obovate to suborbiculate, 1.7–6.5 × 1–5.2 cm, base cuneate to rounded, unlobed, margins moderately to coarsely doubly serrate, apex acute to rounded, abaxial surfaces with bristles on midvein or unarmed, glabrous or sparsely hairy, sparsely to densely short-stipitate-glandular along largest veins.

Inflorescences

terminal, 10–60-flowered, paniculiform or thyrsiform.

terminal on short shoots, usually appearing axillary, 1–7(–10)-flowered, racemiform.

Pedicels

unarmed or prickles moderate to dense, erect to hooked, densely short-hairy, eglandular.

unarmed or bristles moderate to sometimes dense, erect to retrorse, moderately to densely hairy, sparsely to densely short- to long-stipitate-glandular.

Flowers

bisexual;

petals usually pink, sometimes white, obovate or elliptic to suborbiculate, 5–12 mm;

filaments filiform;

ovaries apically hairy.

bisexual;

petals white, obovate to oblanceolate, 6–10 mm;

filaments filiform;

ovaries glabrous.

Fruits

black, globose to ovoid, 1–1.5 cm;

drupelets 10–40, strongly coherent, separating with torus attached.

black, globose to cylindric, to 1 cm;

drupelets (5–)10–15(–20), strongly coherent, separating with torus attached.

2n

= 14.

= 14, 21, 28, 35, 56.

Rubus ulmifolius

Rubus hispidus

Phenology Flowering May–Jul. Flowering May–Jul(–Aug).
Habitat Woodland edges, open areas, disturbed areas, moist soil Moist to wet woodlands, meadows, openings, bogs, fens, disturbed areas, wet to dry soil
Elevation 0–500 m (0–1600 ft) 0–1500 m (0–4900 ft)
Distribution
from FNA
CA; NJ; NV; OR; WA; s Europe; c Europe; n Africa [Introduced in North America; introduced also in s South America]
[WildflowerSearch map]
[BONAP county map]
from FNA
CT; DC; DE; GA; IL; IN; KY; MA; MD; ME; MI; NC; NH; NJ; NY; OH; PA; RI; SC; TN; VA; VT; WA; WI; WV; NB; NF; NS; ON; PE; QC
[WildflowerSearch map]
[BONAP county map]
Discussion

Rubus ulmifolius can be distinguished, especially from the closely related R. bifrons and R. vestitus, by its strongly pruinose stems, finely serrate leaflets, and lack of glands throughout. Unlike R. ulmifolius, strongly pruinose native Rubus species lack relatively large and showy pink petals. Some new stems developing from tip-rooting, and early leaves on such stems (especially in shade), are not whitened abaxially and are tomentose. Such unusual stems develop typical leaves and surfaces in parts formed later.

There has been nomenclatural confusion over unarmed plants of Rubus ulmifolius (see E. Monasterio-Huelin and H. E. Weber 1996). Rubus inermis Willdenow is an illegitimate later homonym of R. inermis Pourret, and the type specimens for both names are of poor-quality. If an unarmed variety of R. ulmifolius is to be recognized, such as occurs in California, the name var. anoplothyrsus Sudre should be used instead of var. inermis (Willdenow) Focke.

Rubus ulmifolius is attractive and is potentially weedy but relatively uncommon, found primarily in coastal California from the San Francisco Bay region southward. It probably no longer persists in New Jersey, last collected there in 1897, and it is rare in Nevada and Oregon. Rubus ulmifolius likely hybridizes with R. bifrons where they co-occur; it is one of relatively few diploid and sexually reproducing species of European blackberries.

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

Rubus hispidus is identified mostly by its creeping primocanes with somewhat lustrous, coriaceous, and relatively small leaves that persist for nearly a year, and an armature of stiff hairs or, rarely, weak, slender prickles. Plants with few persistent leaves may be evidence of introgression with R. flagellaris or R. setosus. Hybrids with R. cuneifolius have been seen around abandoned commercial cranberry bogs in New Jersey (G. Moore, pers. obs.). The superficially similar R. caesius differs from R. hispidus in its pruinose stems, deciduous and non-lustrous leaves, and pruinose fruit.

Rubus hispidus is introduced in southwestern Washington State.

The following nothospecies names are based on putative hybrids involving Rubus hispidus and: R. canadensis (R. ×novanglicus L. H. Bailey); R. flagellaris (R. ×ambigens Fernald, R. ×distinctus L. H. Bailey, R. ×elongatus Brainerd & Peitersen [not R. elongatus Smith], R. ×emeritus L. H. Bailey, R. ×furtivus L. H. Bailey, R. ×kalamazoensis L. H. Bailey, R. ×permixtus Blanchard, R. ×rosendahlii L. H. Bailey, R. ×segnis L. H. Bailey, R. ×varus L. H. Bailey, R. ×vigoratus L. H. Bailey); R. setosus (R. ×adjacens Fernald, R. ×grandidens L. H. Bailey, R. ×harmonicus L. H. Bailey, R. ×jacens Blanchard, R. ×parlinii L. H. Bailey, R. ×spiculosus Fernald, R. ×tardatus Blanchard, R. ×tholiformis Fernald, R. ×trifrons Blanchard, R. ×zaplutus L. H. Bailey).

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

Source FNA vol. 9, p. 54. FNA vol. 9, p. 41.
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. trivialis, R. ursinus, R. vestitus
R. allegheniensis, R. arcticus, R. bartonianus, R. bifrons, R. caesius, R. canadensis, R. chamaemorus, R. cuneifolius, R. deliciosus, R. flagellaris, R. glaucifolius, 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. discolor, R. ulmifolius var. anoplothyrsus R. blanchardianus, R. compos, R. cubitans, R. davisiorum, R. fassettii, R. hispidus var. blanchardianus, R. hispidus var. cupulifer, R. hispidus var. obovalis, R. huttonii, R. paganus, R. pervarius, R. plus, R. porteri, R. provincialis, R. pudens, R. rowleei, R. signatus, R. trifrons var. pudens, R. vagulus, R. vigil
Name authority Schott: Isis (Oken) 1818: 821. (1818) Linnaeus: Sp. Pl. 1: 493. (1753)
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