Rubus ulmifolius
Rubus illecebrosus
elm-leaf blackberry
strawberry 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.
annual, arching to mounding, glabrous, eglandular, not pruinose;
prickles sparse, slightly hooked, stout, 3–4 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, pinnately compound;
stipules lanceolate to oblanceolate, 8–13 mm;
leaflets (3–)5–7, terminal lanceolate to narrowly ovate, (5.5–)6.2–8.5(–9.7) × (1.8–)2.2–3(–4.2) cm, base usually rounded, sometimes truncate to subcordate, unlobed, margins finely to coarsely doubly serrate, apex acuminate, abaxial surfaces with prickles on midvein, glabrous, eglandular.
terminal, 10–60-flowered, paniculiform or thyrsiform.
solitary flowers or 2–3-flowered clusters.
unarmed or prickles moderate to dense, erect to hooked, densely short-hairy, eglandular.
prickles sparse, slightly hooked, glabrous, eglandular.
bisexual;
petals usually pink, sometimes white, obovate or elliptic to suborbiculate, 5–12 mm;
filaments filiform;
ovaries apically hairy.
bisexual;
petals white, broadly obovate to suborbiculate, 12–15(–18) mm;
filaments laminar;
ovaries glabrous, styles glabrous.
black, globose to ovoid, 1–1.5 cm;
drupelets 10–40, strongly coherent, separating with torus attached.
red, oblong, 1.4–2 cm;
drupelets 50–100, strongly coherent, separating from torus.
= 14.
= 14.
Rubus ulmifolius
Rubus illecebrosus
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 illecebrosus is distinguished from other raspberries by its prickly, glabrous, eglandular stems, pinnately compound leaves with typically seven lanceolate to narrowly ovate leaflets, relatively large flowers, white petals, and 50–100 drupelets.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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