28.Rubus trivialis Michx. (southern dewberry)

Pl. 540 m, n; Map 2526

Canes to 250 cm long and to 70 cm tall, arching to prostrate, typically branched, 3–4 mm in diameter, reddish, often rooting at tips and sometimes at nodes. Primocanes with prickles and dark red hairs, some or all gland-tipped. Prickles moderate, 1–3 per cm of cane, 3–5 mm long, downward angled or downward curved. Petioles with stiff, dark red hairs, some or all gland-tipped, and downward-angled prickles to 2 mm long. Stipules 5–14 mm long, linear to filiform. Primocane leaves mostly with 5 leaflets, less often 3, the margins sharply or bluntly toothed, the upper surface nearly glabrous, the undersurface hairy only on the veins. Central primocane leaflets 5.0–7.5 cm long and 2.5–5.0 cm wide, narrowly elliptic to ovate-elliptic to obovate-elliptic, truncate, rounded, or angled at the base, usually tapered to a sharply pointed tip, but occasionally rounded at tip, the leaflet stalk about 1/6–1/3 as long as the leaflet blade; basal leaflets generally of same form as the central leaflet, but smaller, short-stalked. Primocane leaflets often persist until flowering the following spring, by winter typically appearing bronzed. Inflorescences 5–18 cm long, with 1–3(4) flowers on long, ascending stalks and 2–6 leafy bracts, these mostly with 3 leaflets; flower and inflorescence stalks thinly covered with light-colored, nonglandular hairs and sometimes with red, glandular hairs, and needlelike or downward-curved prickles. Sepals 4–6(–9) mm long, 2–5 mm wide, narrowly triangular, tapered to a pointed tip or abruptly tapered to a short, slender point. Petals 10–14(–18) mm long, obovate to broadly obovate, white or sometimes pinkish-tinged. Fruits 10–30 mm long, 9–12 mm wide, oblong. 2n=14. April–June.

Scattered, mostly south of the Missouri River, most abundantly in the Mississippi Lowlands Division (southeastern U.S. west to Oklahoma and Texas; Mexico). Banks of streams and rivers, bases and ledges of bluffs, bottomland forests, swamps, and sloughs; also pastures, fallow fields, levees, and roadsides.

This attractive species is distinctive in its abundant, red, prickles and bristly hairs, some of which are gland-tipped. As in some other species of Rubus, it produces long, white roots that are fleshy and somewhat thickened, which can give rise to new canes at quite some distance from the original clump.