Large spreading shrubs or small to moderate sized trees, 2–8 m high; trunks reaching 5–20 cm in diameter, glabrate, usually armed with large conical prickles 1–5 cm long; flowering stems glabrate and dark except on very young developing portions; prickles often absent on flowering stems, if present very sparse, 2–5 mm long, broad-based, laterally compressed.
Sympodial units difoliate, geminate.
Leaves simple, those on flowering stems with blades 10–35 × (3–) 8–21 cm, ca. 2 times as long as wide, ovate to broadly ovate, more rarely lanceolate, chartaceous, strongly bicolorous, glabrate green adaxially, the stellae deciduous during leaf expansion, these sessile or very short stalked, 8–14 rayed, 0.5–0.7 mm in diameter, without recognizable midpoints, densely white pubescent abaxially, the stellae densely overlapping, persistent, short stalked, 10–16 rayed, 0.6–0.8 mm in diameter, lacking midpoints; major veins impressed adaxially, the midvein and the 5–6 principal lateral veins persistently tomentose or soon glabrate abaxially; blades usually unarmed; base asymmetrically obtuse or rounded; margin sinuate–repand to entire; apex acuminate; petioles of major leaves 3–8 cm, soon glabrate and dark like the stems, unarmed or occasionally with a few small prickles; juvenile leaves very large and more prickly than those on flowering stems, usually pinnatifid.
Inflorescences 3–13 cm in flower, larger in fruit, extra-axillary, usually unequally bifurcate at or near base or at times short pedunculate, usually with one or both branches further branched, the ultimate racemose branches 2–6.5 cm long, with 5–20 flowers, the axes with dense and velvety stellate pubescence much like that of leaf undersides, variously persistent or deciduous, unarmed; peduncle 0–1.6 cm; rachis 3.2–8 cm; pedicels 4–7 mm in flower, to 10 mm in fruit, stout, persistently stellate woolly, spaced ca. 1 mm apart, articulated at the base.
Flowers apparently all fertile although fewer fruits forming than flowers, 5-merous. Calyx 2–5 mm long, the tube 2–3 mm, 4–6 mm in diameter, broadly campanulate, the lobes low, 1–3 × 1.8–3 mm, broadly deltoid or rounded and apiculate, sometimes oblong in age, densely stellate woolly abaxially, glabrous adaxially; fruiting calyx not or only weakly accrescent. Corolla 1.5–2.5 cm in diameter, 12–16 mm long, stellate, white, pale violet or occasionally deeper purple, the central portion linear-lanceolate, densely and minutely white-stellate abaxially, with a small amount of glabrous interpetalar tissue in the sinus, the tube 3–6 mm, the lobes 6–13 × 3.5–6 mm, ovate lanceolate, acute at apices, adaxially with a single row of minute stellae along the central nerve, occasionally glabrous. Stamens free; filaments 2–2.9 mm, glabrous; anthers 4–5.5 × 1-1.6 mm, slender, tapering, yellow, the pores directed distally. Ovary glabrous; style 7–9 mm, filiform, slightly expanded distally, well exceeding the anthers, glabrous; stigma capitate.
Fruit a berry 0.8–1.5 cm in diameter, globose, dull yellow when ripe, eventually turning black, glabrous.
Seeds numerous, 1.8–2.3 × 1.7-2.1 mm, lenticular, broadly asymmetric ovate, yellow or yellow brown, the surface minutely pitted.
Shrubby ravine slopes, clearings and understories of open seasonal woodlands, margins of watercourses, alluvial flats, and disturbed or overgrazed places, 750–2200 m, in the Andes except for rarely spreading out onto the agricultural plains near Buena Vista in Depto. Santa Cruz, Bolivia, 270 m; common at middle elevations in the Andes from Provs. El Oro and Loja in southern Ecuador south to Depts. Ayacucho and Apurimac in Peru, Bolivia, and to Prov. Salta in northwestern Argentina.