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elm-leaf blackberry

snow bramble, thimbleberry

Habit Shrubs, 30–50 dm, unarmed or armed. Shrubs, 5–20(–30) dm, unarmed.
Stems

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, sparsely hairy, glabrescent, moderately stipitate-glandular, glands yellowish to reddish, not pruinose.

Leaves

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 ovate, 5–15 mm;

blade orbiculate to reniform, 5–20 × 5–25 cm, base cordate, palmately, shallowly to moderately deeply, (3–)5(–7)-lobed, margins coarsely, irregularly serrate to doubly serrate, apex shortly acuminate to obtuse, abaxial surfaces glabrate to densely hairy, sparsely to moderately stipitate-glandular, glands yellowish to reddish.

Inflorescences

terminal, 10–60-flowered, paniculiform or thyrsiform.

terminal and axillary, (1–)3–7(–15), cymiform to thyrsiform.

Pedicels

unarmed or prickles moderate to dense, erect to hooked, densely short-hairy, eglandular.

sparsely to moderately hairy, moderately to densely stipitate-glandular, glands yellowish to reddish.

Flowers

bisexual;

petals usually pink, sometimes white, obovate or elliptic to suborbiculate, 5–12 mm;

filaments filiform;

ovaries apically hairy.

bisexual;

petals white, broadly obovate, (10–)14–22(–28) mm;

filaments filiform;

ovaries distally densely hairy, styles clavate, glabrous.

Fruits

black, globose to ovoid, 1–1.5 cm;

drupelets 10–40, strongly coherent, separating with torus attached.

red, hemispheric, 1–1.8 cm;

drupelets 50–60, coherent, separating from torus.

2n

= 14.

= 14.

Rubus ulmifolius

Rubus parviflorus

Phenology Flowering May–Jul. Flowering May–Aug.
Habitat Woodland edges, open areas, disturbed areas, moist soil Moist areas, open woods, thickets, clearings, stream banks, canyons, grassy meadows, rocky cliffs, sand dunes, upper beaches, dry sandy areas, roadsides
Elevation 0–500 m (0–1600 ft) 0–3000 m (0–9800 ft)
Distribution
from FNA
CA; NJ; NV; OR; WA; s Europe; c Europe; n Africa [Introduced in North America; introduced also in s South America]
[WildflowerSearch map]
[BONAP county map]
from FNA
AK; AZ; CA; CO; IA; ID; IL; MI; MN; MT; NM; NV; OR; SD; UT; WA; WI; WY; AB; BC; ON; Mexico (Chihuahua)
[WildflowerSearch map]
[BONAP county map]
Discussion

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 nutkanus is distinguished from other flowering raspberries by its erect, unarmed stems, simple leaves, large flowers, white petals, glabrous, clavate styles, and yellowish to reddish stipitate glands covering most plant parts. A hybrid with R. odoratus (R. ×fraseri Rehder) is thought to occur in areas of overlap in northern Michigan (E. G. Voss 1972–1996, vol. 2). Varieties and forms have been described based on indument and glandularity of stems, leaves, petioles, pedicels, and sepals (for example, M. L. Fernald 1950). Different variants often occur mixed in the same population and generally do not correspond to definite geographic regions (N. C. Fassett 1941). Plants from coastal California (considered as var. velutinus) tend to have densely hairy leaf abaxial surfaces; this variation may be environmentally induced; other Rubus species show the same pattern (for example, R. spectabilis var. franciscanus) in that area. Wild thimbleberries are collected in Keweenaw Peninsula, Michigan, and are used in beverages and especially for jam.

Rubus nutkanus is typically associated with western North America but was originally described from plants at its eastern range limit in northern Michigan. The Great Lakes populations are disjunct from western mountain populations by around 600 miles.

The name Rubus parviflorus var. grandiflorus Farwell, which applies here, is illegitimate.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Source FNA vol. 9, p. 54. FNA vol. 9, p. 48.
Parent taxa Rosaceae > subfam. Rosoideae > tribe Rubeae > Rubus Rosaceae > subfam. Rosoideae > tribe Rubeae > Rubus
Sibling taxa
R. allegheniensis, R. arcticus, R. bartonianus, R. bifrons, R. caesius, R. canadensis, R. chamaemorus, R. cuneifolius, R. deliciosus, R. flagellaris, R. glaucifolius, R. hispidus, R. idaeus, R. illecebrosus, R. laciniatus, R. lasiococcus, R. leucodermis, R. neomexicanus, R. nivalis, R. niveus, R. nutkanus, R. occidentalis, R. odoratus, R. parviflorus, R. parvifolius, R. pascuus, R. pedatus, R. pensilvanicus, R. phoenicolasius, R. pubescens, R. repens, R. saxatilis, R. setosus, R. spectabilis, R. trivialis, R. ursinus, R. vestitus
R. allegheniensis, R. arcticus, R. bartonianus, R. bifrons, R. caesius, R. canadensis, R. chamaemorus, R. cuneifolius, R. deliciosus, R. flagellaris, R. glaucifolius, R. hispidus, R. idaeus, R. illecebrosus, R. laciniatus, R. lasiococcus, R. leucodermis, R. neomexicanus, R. nivalis, R. niveus, R. nutkanus, R. occidentalis, R. odoratus, R. parvifolius, R. pascuus, R. pedatus, R. pensilvanicus, R. phoenicolasius, R. pubescens, R. repens, R. saxatilis, R. setosus, R. spectabilis, R. trivialis, R. ulmifolius, R. ursinus, R. vestitus
Synonyms R. discolor, R. ulmifolius var. anoplothyrsus R. parviflorus
Name authority Schott: Isis (Oken) 1818: 821. (1818) Mociño ex Seringe: in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 2: 566. (1825)
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