Rubus ulmifolius
Rubus setosus
elm-leaf blackberry
bristly blackberry, ronce sétuleuse, setose blackberry
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, erect to arching, rarely creeping, not node- or tip-rooting, sparsely to moderately hairy, sparsely to densely long-, rarely short-stipitate-glandular, glands rounded to flattened, not pruinose;
prickles absent or sparsely to moderately dense, erect to retrorse, weak, slender, 1–3(–5) mm, narrow-based;
bristles sparse to dense, erect to retrorse, green to reddish, narrow, semirigid, sometimes flexible, not gland-tipped.
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.
deciduous, ternate or palmately compound, sometimes ± lustrous;
stipules filiform to lanceolate, 5–20(–38) mm;
leaflets (3–)5, terminal obovate or elliptic to rhombic, 4.5–11.5 × 2–7 cm, base cuneate to narrowly rounded, unlobed, margins moderately, coarsely serrate to doubly serrate or serrate-dentate, apex acute or acuminate to short-attenuate, abaxial surfaces unarmed or with bristles on midvein, sparsely to moderately hairy, eglandular or sparsely to moderately sessile- to long-stipitate-glandular along larger veins.
terminal, 10–60-flowered, paniculiform or thyrsiform.
terminal on short shoots, sometimes appearing axillary, 5–15(–20)-flowered, racemiform, cymiform, or thyrsiform.
unarmed or prickles moderate to dense, erect to hooked, densely short-hairy, eglandular.
prickles or bristles sparse to dense, erect to retrorse, moderately to densely hairy, moderately to densely stipitate-glandular.
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, 6–13 mm;
filaments filiform;
ovaries glabrous.
black, globose to ovoid, 1–1.5 cm;
drupelets 10–40, strongly coherent, separating with torus attached.
black, globose, 0.7–1.5 cm;
drupelets 5–25, strongly coherent, separating with torus attached.
= 14.
= 14, 21, 28, 35.
Rubus ulmifolius
Rubus setosus
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 setosus is identified by erect to arching, rarely creeping, not tip-rooting, terete primocanes, always setose but variable in density, and deciduous primocane leaves that are often palmately compound with five leaflets. Cultivated plants sometimes alternate from erect to creeping (or vice-versa) in successive years, depending on changing soil conditions.
The following nothospecies names are based on putative hybrids involving Rubus setosus and: R. allegheniensis (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); R. canadensis (R. ×miscix L. H. Bailey [based on R. ×peculiaris Blanchard (not R. peculiaris Sampaio)]); R. flagellaris (R. ×alter L. H. Bailey, R. ×arcuans Fernald & H. St. John, R. ×biformispinus Blanchard, R. ×bigelovianus L. H. Bailey, R. ×bracteolifer Fernald, R. ×jacens Blanchard var. specialis L. H. Bailey, R. ×laevior (L. H. Bailey) Fernald [based on R. permixtus var. laevior L. H. Bailey], R. ×multiformis Blanchard, R. ×setospinosus L. H. Bailey, R. ×severus Brainerd ex Fernald); R. hispidus (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); R. pensilvanicus (R. ×wisconsinensis L. H. Bailey).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
CA, 
OR, 
WA - Local Web sites: CalFlora, CalPhotos,
Flora NW, 
PNW Herbaria 
WildflowerSearch
iNaturalist (observations)
USDA Plants Database- LBJ Wildflower Center
- SEINet
- Plants of the World Online
- Encyclopedia of Life
- Wikipedia
- Google Image Search
Go Botany
IL Wildflowers
MD Biodiversity
MI Flora
MN Wildflowers
