Wild potato

Herbs, perennial, erect, unarmed, bearing tubers to 2 cm long, to 0.5 m, glabrous or sparsely pubescent, hairs unbranched, gland-tipped. Leaves petiolate; petiole 1.5–3.5 cm, sometimes with pair of pinnatifid pseudo­stipules at base; blade com­pound, elliptic to ovate, 7–15 × 4–9 cm, margins divided into 1–4(–5) pairs of leaflets, leaflet margins entire, base attenuate. Inflorescences ter­minal, extra-axillary, generally forked or 3-fid, 4–10(–20)-flowered, to 3 cm. Pedicels artic­ulated near middle, 1.6–3 cm in flower and fruit. Flowers radially symmetric; calyx not accrescent, unarmed, 4–6 mm, glabrous to sparsely pubescent, lobes deltate-acuminate; corolla white, stellate, 2.8–3.5 cm diam., without inter­petalar tissue; stamens equal; anthers oblong, slightly tapered, 5–6 mm, dehiscent by terminal pores that open into longitudinal slits; ovary glabrous. Berries green, globose, ca. 1 cm diam., gla­brous, without sclerotic granules. Seeds dark reddish brown, rounded, 1–2 mm diam., rugose. 2n = 24.

Flowering Jun–Oct. Hillsides, stream bottoms, sandy soils, disturbed grasslands, pinyon-juniper forests, oak thickets, coniferous and deciduous forests; 1300–2900 m; Ariz., Colo., N.Mex., Tex., Utah; Mexico (Chihuahua, Querétaro, San Luis Potosí, Sonora).

The tubers of Solanum jamesii have been gathered as food by Native Americans, and starch grains identified as S. jamesii from stone tools in Utah form the earliest evidence for the use of potatoes in North America (L. A. Louderback and B. M. Pavlik 2017). All other parts of the plant are toxic.