Rubus ulmifolius
Rubus vestitus
elm-leaf blackberry
European 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, arching, usually densely, sometimes moderately, hairy, usually eglandular, sometimes sessile- to short-stipitate-glandular, not pruinose;
prickles moderate to dense, recurved to erect, slender, 3–10 mm, broad-based.
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 or ± persistent, palmately compound;
stipules filiform to linear, 5–15 mm;
leaflets 3–5, terminal usually suborbiculate to orbiculate, sometimes broadly elliptic, 4–9 × 4–8 cm, base rounded to shallowly cordate, unlobed, margins moderately to coarsely serrate, apex acute to cuspidate, abaxial surfaces with hooked prickles on midvein, densely white-gray to gray-green tomentose, eglandular or obscurely short-stipitate- to sessile-glandular along midveins.
terminal, 10–60-flowered, paniculiform or thyrsiform.
terminal, 7–35-flowered, cymiform or thyrsiform.
unarmed or prickles moderate to dense, erect to hooked, densely short-hairy, eglandular.
prickles moderate to dense, recurved to erect, 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 pink to magenta, elliptic to suborbiculate, 6–12(–15) mm;
filaments filiform;
ovaries apically hairy.
black, globose to ovoid, 1–1.5 cm;
drupelets 10–40, strongly coherent, separating with torus attached.
black, globose, 1–1.5 cm;
drupelets 15–40, coherent, separating with torus attached.
= 14.
= 28.
Rubus ulmifolius
Rubus vestitus
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 vestitus can be distinguished, especially from the closely related R. bifrons and R. ulmifolius, by its long-stipitate-glandular hairs, particularly in the inflorescence, and terminal primocane leaflets that are typically suborbiculate and abaxially densely tomentose. Rubus allegheniensis can possess similar glandular hairs; it does not have pink petals, thyrsiform inflorescences, and rounded and abaxially densely tomentose, often whitened terminal leaflets.
Rubus vestitus has not yet been found in Washington, but it is likely there. Because of the overall similarity of R. vestitus to R. bifrons, it is possible that this potentially weedy species is widespread, but rare and possibly overlooked, occurring as far south as California. In Oregon, R. vestitus prefers shady habitats (B. Wilson, pers. comm.).
(Discussion copyrighted by Flora of North America; reprinted with permission.)
- Local floras:
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OR, 
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Flora NW, 
PNW Herbaria 
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- Local floras:
BC, OR, WA - Local Web sites: Flora NW, PNW Herbaria
- WildflowerSearch
- iNaturalist (observations)
- USDA Plants Database
- LBJ Wildflower Center
- SEINet
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- Encyclopedia of Life
- Wikipedia
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