PLANT: Woody shrubs or vines; stems (canes) usually only biennial and temporally dimorphic; first year canes (primocanes) usually vegetative; second year canes (floricanes) bearing flowers; prickles if present found on canes, leaves, and inflorescences. LEAVES: pinnately or palmately compound, or palmately lobed; primocane leaves often larger and with more leaflets than floricane leaves; stipules conspicuous, usually persistent, adnate to the petiole in ours, broad or linear. INFLORESCENCE: uniflorous or few‑many‑flowered cymes. FLOWERS: perfect, perigynous; hypanthium small; sepals 5, ascending to reflexed, commonly mucronate or caudate; petals 5, oblanceolate or spatulate to ovate, white to reddish; stamens many, distinct, erect; pistils many, on a convex to conical torus that enlarges in fruit, the styles terminal. FRUIT: a flat to conical aggregate of sweet, fleshy or dry drupelets which separate from the torus (raspberries) or not (blackberries, dewberries). x = 7. NOTES: 200‑700 spp., 6 in AZ, temperate and tropical-montane, especially complex in Eur. and e N. Amer. (Latin: Pliny, rubus for bramble or blackberry). Bailey, L. H. 1941‑1945. Gentes Herb. 5:1‑932. Taxonomy complicated by hybridization, polyploidy, and apomixis. Collectors should include floricanes, primocanes, and notes regarding growth habit. Both R. neomexicanus and R. parviflorus are reported to be extensively browsed by deer. Native Americans reportedly ate the young shoots of R. parviflorus and R. idaeus, and made a tea of R. parviflorus leaves. Rubus discolor, R. idaeus, and R. leucodermis include fruit cultivars. REFERENCES: Brasher, Jeffrey W. 2001. Rosaceae. J. Ariz. - Nev. Acad. Sci. Volume 33(1).
Perennial subshrub or herb Stem: erect to trailing, usually prickly, often short-lived. Sometimes stems are biennial, with vegetative growth occurring in the first year and flowers and fruit produced the second year. Leaves: alternate, having an often prickly stalk with narrow stipules at the base, usually compound with three to five leaflets, sometimes simple, variable in size, toothed or lobed. Biennial stems usually have compound leaves the first year and have both compound and simple leaves the second year. Flowers: sometimes unisexual but usually bisexual, white to pink or red, usually borne on an inflorescence with the terminal flowers opening first (determinate), sometimes solitary, having numerous stamens and pistils, club-shaped to thread-shaped styles, and two side-by-side ovules (only one maturing). Pistils are attached to a convex to conic, enlarged end of the stalk (receptacle) which usually lengthens in fruit. Sepals: usually five, often subtended by five bracts, fused at the base, with lobes that are spreading to reflexed or meet at the edges but do not overlap (valvate). Petals: usually five, spoon-shaped to inversely egg-shaped or elliptic, erect to spreading, sometimes short-lived. Fruit: a cluster of small fleshy fruits (sometimes dry), each having a hard center seed (drupelets). Drupelets usually fall from the plant together but sometimes fall separately, and the receptacle may fall with the drupelets or remain on the stalk.
Flowering: spring to early summer
Habitat and ecology: Usually found in disturbed habitats, often in thickets, woods, or edges of woods. Some Rubus species are native, while others are introduced and sometimes escape into natural areas.
Notes: The genus Rubus includes blackberries, raspberries, thimbleberries, and dewberries. Species within the genus hybridize readily, adding to the already complicated taxonomy of Rubus.
Etymology: Rubus is the Latin name for bramble and also means red.
Hypanthium small, flat to hemispheric; sep usually 5, valvate, spreading to reflexed, commonly with a shortly caudate tip; bractlets none; pet as many as the sep, erect or spreading, spatulate to obovate or elliptic; stamens numerous; pistils numerous, inserted on a convex to conic receptacle that often elongates in fr; ovules 2, collateral, only one maturing; style filiform or clavate; fr a cluster of drupelets, falling together (or sometimes separately), the receptacle falling with the cluster of drupelets or remaining attached to the pedicel; shrubs or less often perennial herbs, very often prickly, with simple or more commonly compound, serrate or lobed lvs and small to large, perfect or unisexual, white to pink or red fls; infl determinate, but commonly with the aspect of a raceme or corymb or panicle; x=7. 200+, cosmop.
In subgenera Rubus and Idaeobatus the plant sends up from a perennial base a series of biennial stems. During their first year these are termed primocanes; they are usually unbranched and normally do not fl. During their second year they are known as floricanes; they increase no more in length, but emit a number of short lateral branches with a few lvs and usually a terminal fl or infl. The lvs of the primocane are compound; those of the floricane are often partly simple, and often of a different shape.
Most of the spp. of subg. Rubus grow in disturbed habitats, often representing an early stage in plant succession. Different species may grow intermingled in such places. Some of the same species also grow in more stable habitats, with some sorting out of species by habitat.
The taxonomy of Rubus is complicated by hybridization, polyploidy, and apomixis. The subgenus Rubus (blackberries) is particularly difficult, and the conservative treatment here presented is subject to extensive change when a proper biosystematic study can be made. Some of the many names listed in synonymy should probably be transferred to the partial list of putative hybrids, hybrid segregates, and local populations of hybrid origin presented below.
R. ءculiferus Fernald = R. allegheniensis נsetosus
R. ءdjacens Fernald = R. hispidus נsetosus
R. ءlter L. H. Bailey = R. hispidus נsetosus
R. ءrcuans Fernald & H. St. John = R. recurvicaulis נsetosus
R. آicknellii L. H. Bailey = R. recurvicaulis נsetosus
R. آiformispinus Blanch. = R. allegheniensis נhispidus
R. آiformispinus Blanch. = R. allegheniensis נhispidus
R. آlanchardianus L. H. Bailey = R. hispidus נsetosus
R. إlectus L. H. Bailey = R. allegheniensis נhispidus
R. اlandicaulis Blanch. = R. allegheniensis נsetosus
R. بarmonicus L. H. Bailey = R. hispidus נsetosus
R. تacens Blanch. = R. hispidus נsetosus
R. تactus L. H. Bailey = R. allegheniensis נhispidus [Continued]
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.