Rubus trivialis Michx., southern dewberry. Woody climber, spinescent, not rosetted, several–stemmed at base, with arching to trailing perennial branches, growing along the ground and on itself or neighboring plants; shoots with only cauline leaves, axes with backward–curved and straight prickles.
Stems tough, internodes to 50 mm long, having backward–curved to straight prickles with broad bases.
Leaves helically alternate, pinnately 3—5–foliolate (appearing palmately compound), petiolate with pulvinus, with stipules; stipules 2, attached to lower petiole, acuminate–narrowly lanceolate to narrowly elliptic or linear, 3—3.8(—7) × (0.35—)0.5—0.6 mm, green; petiole channeled (including pulvinus), to 50 mm long, having backward–curved prickles with broad bases (not in channel), prickles to 3 mm long; rachis channeled, 6.5—18 × 0.5 mm, with some prickles on lower side; petiolules of lateral leaflets 0—0.4 mm long; blades of leaflets unequal, ovate to broadly elliptic in outline (lateral leaflets asymmetric), 40—55 × 25—42 mm, if 3–foliolate lateral leaflets often 2–lobed, tapered at base, short–lobed and serrate to 2–serrate on margins having acute principal teeth, acute at tip, pinnately veined with principal veins raised on lower surface, lower surface with short prickles along midrib.
Inflorescence cyme, 1(—3)–flowered, terminal and often erect on short lateral shoot, lateral shoots < 70 mm long, bractlet subtending pedicel petiolate and leaflike but 1–foliolate, resembling a terminal leaflet, with 2 stipules fused to lower petiole, stipules free portion narrowly triangular, to 6 mm long, petiole channeled, to 7 mm long, with 1—several prickles on lower side, short–tomentose, blade ovate, to 20 × 13 mm, 1—2–serrate on margins with purple–red teeth, pinnately veined with principal veins sunken on upper surface and raised on lower surface, upper surface ± glabrous, lower surface short–hairy along veins.
Flower bisexual, radial, in range 22—38 mm across; receptacle conic, with hairs between pistils; hypanthium shallowly dishlike, to 6 mm across, green, soft–hairy, not glandular–hairy, nectary green tissue below stamens, nectar–producing; sepals 5, arising from rim of hypanthium, broadly ovate cupped and reflexed, 5.5—8 × 4.5—5.5 mm, conspicuously folded along midline, with 1—3 points at tip 2—3 mm long with glands along margins, surfaces soft–hairy, on upper surface strongly appressed; petals 5, widely spreading, 16—23.5 mm long, white, limb ± round, 13—19 mm, with a clawlike base (not really a claw) fan–shaped, with several radiating veins from base; stamens 100+ in several series, on rim of hypanthium, free (not in clusters); filaments unequal, 2.5—6.2 mm long decreasing outer stamens to inner stamens, white, glabrous; anthers dorsifixed, dithecal, 1.1—1.4 mm long, cream–colored aging deep rose, longitudinally dehiscent; pollen white; pistils 25+, helically alternate on conic receptacle (torus), 4—4.5 mm long; ovaries superior, ellipsoid to ovoid, 0.7—0.8 × 0.45—0.5 mm, dull green, glabrous, 1–chambered with 1 ovule; style cylindric, curved or crooked, yellowish to pale green, stigmatic at oblique and channeled tip.
Fruit aggregate fruit of 12—25 fleshy 1–stoned drupelets from 1 flower, in a hemispheric to conelike cluster, having walls fused at base via a fleshy receptacle, aggregate 12—16 mm diameter; drupelets helically arranged, subspheroid to obovoid or oblate mutually compressed below midpoint, 3.5—4.5 × 4—5 mm, at maturity black, glabrous; style ± persistent; pulp (mesocarp) juicy, sweet, dark red; stone (endocarp, putamen) D–shaped, ca. 3 × 2 × 1.3 mm, tan but often stained darker from pulp, extremely hard, conspicuously netlike, ridged around edge.
A. C. Gibson