Rubus ulmifolius
Rubus laciniatus
elm-leaf blackberry
cut-leaf blackberry, cutleaf evergreen blackberry, evergreen 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, sometimes creeping, glabrate to moderately hairy, sparsely to densely sessile- to short-stipitate-glandular, not or weakly pruinose;
prickles moderately dense to dense, suberect to retrorse or hooked, stout, 2–8 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.
evergreen to late-deciduous, ternate or palmately compound;
stipules filiform, 5–15 mm;
leaflets 3–5, terminal ovate to elliptic, 6–12 × 7–12 cm, base rounded to cordate, usually deeply, rarely shallowly, lobed, margins coarsely serrate to doubly serrate, apex acuminate to short-attenuate, abaxial surfaces with hooked prickles primarily on midvein, moderately to densely hairy, eglandular or moderately sessile- to short-stipitate-glandular primarily on midvein.
terminal, 10–60-flowered, paniculiform or thyrsiform.
terminal, 5–25-flowered, thyrsiform.
unarmed or prickles moderate to dense, erect to hooked, densely short-hairy, eglandular.
prickles moderate to dense, erect to reflexed, densely hairy, moderately to densely sessile- to short-stipitate-glandular.
bisexual;
petals usually pink, sometimes white, obovate or elliptic to suborbiculate, 5–12 mm;
filaments filiform;
ovaries apically hairy.
bisexual;
petals white to pink, elliptic to obovate, 8–15 mm;
filaments filiform;
ovaries usually apically hairy.
black, globose to ovoid, 1–1.5 cm;
drupelets 10–40, strongly coherent, separating with torus attached.
black, globose to subcylindric, 1–1.5 cm;
drupelets 25–60, strongly coherent, separating with torus attached.
= 14.
= 28.
Rubus ulmifolius
Rubus laciniatus
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 laciniatus is the only blackberry in the flora area that has leaflets so deeply lobed and dissected or has 3-lobed petals. Rare individuals bearing relatively unlobed leaflets and perianth parts may be part of the natural variation of this species or be hybrids with some other species. Putative natural hybrids have been reported with R. bifrons (as R. procerus; R. K. Bammi and H. P. Olmo 1966). Such unusual plants of R. laciniatus would be distinguished from the native blackberries by their thyrsiform and notably stipitate-glandular inflorescences and evergreen to late-deciduous leaves.
Although widely introduced in the flora area, Rubus laciniatus is a less aggressive weed than R. bifrons.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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