Rubus ulmifolius
Rubus deliciosus
elm-leaf blackberry
boulder raspberry, delicious raspberry
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.
decumbent to erect, glabrous or sparsely short-hairy, eglandular or sparsely stipitate-glandular, not pruinose.
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, simple;
stipules lanceolate to narrowly ovate, 5–8(–14) mm;
blade orbiculate to reniform, (1.5–)2–4(–5) × (2.5–)3–4.5(–7) cm, base shallowly cordate, 3–5(–7)-lobed, lobe apices broadly rounded to obtuse, margins doubly dentate, abaxial surfaces sparsely hairy, mostly along veins, sparsely stipitate-glandular.
terminal, 10–60-flowered, paniculiform or thyrsiform.
1-flowered.
unarmed or prickles moderate to dense, erect to hooked, densely short-hairy, eglandular.
pubescent, sparsely to densely short- to long-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 ovate, 15–25(–30) mm;
filaments filiform;
ovaries glabrous, styles clavate, villous.
black, globose to ovoid, 1–1.5 cm;
drupelets 10–40, strongly coherent, separating with torus attached.
dark purple, hemispheric, to 1 cm;
drupelets 10–40, coherent, separating from torus.
= 14.
= 14, 21.
Rubus ulmifolius
Rubus deliciosus
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 deliciosus is recognized by its decumbent to erect, unarmed stems, relatively small simple leaves with obtuse to broadly rounded lobes, shallowly cordate bases, sparsely hairy abaxial surfaces, large flowers, white petals, glabrous or sparsely hairy sepals, and densely villous clavate styles. The distinction between R. deliciosus and R. neomexicanus is not always clear, especially when the former has more narrowly obtuse lobes and denser leaf abaxial hairs. Rubus deliciosus is also similar to R. bartonianus of Idaho and Oregon, as well as the Mexican R. trilobus Seringe. It might be reasonable to recognize a broader concept of R. deliciosus, one containing multiple infraspecific. Rubus deliciosus and its close relatives require a revisionary study.
Rubus deliciosus has long been planted for its ornamental value because of its large, showy flowers.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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