Sonoran nightshade

Herbs, annual, erect, moderately to densely armed, 0.2–0.7 m, prickles whitish or yellowish, straight, bristlelike, 4–8 mm, 20+ per cm of stem, sparsely pubescent, hairs sessile to short-stalked, unbranched, glandular, sometimes with a few unbranched, eglandular hairs, abaxial leaf surfaces with sparse, sessile, 4–6-rayed, stellate hairs, central ray equal to lateral rays. Leaves petiolate; petiole 2.5–6.5 cm; blade simple to compound, broadly ovate, 5–13 × 2.5–9 cm, margins 2–3-times lobed or divided with 4–5 main leaflets per side, leaflets with deep, acute lobes, base truncate. Inflorescences extra-axillary, unbranched, 6–10-flowered, 3–8 cm. Pedicels 0.5–1.5 cm in flower, erect and 0.5–1.5 cm in fruit. Flowers bilaterally symmetric; calyx accrescent and tightly covering fruit, densely prickly, 3.5–4.5 mm, sparsely to moderately glandular-pubescent, lobes linear-lanceolate; corolla yellow, stellate, 1.3–1.8 cm diam., with ovate or narrowly deltate lobes, with sparse interpetalar tissue; stamens unequal, lowermost longer and curved, adjacent pair somewhat shorter, uppermost pair shortest; anthers narrow and tapered, dehiscent by terminal pores, shortest anthers 4.5–6 mm, medium-sized anthers 5.6–7.5 mm, longest anther 6.5–8.6 mm; ovary glabrous. Berries brown, globose, 1–1.4 cm diam., glabrous, dry, without sclerotic granules. Seeds dark brown, plump, 3–3.5 × 2.5–3 mm, radially ridged with hilum sunken in a deep notch. 2n = 24.

Flowering Aug–Oct. Sandy or gravelly soils, washes, low ground near wet depressions, along stream banks, roadsides; 900–1400 m; Ariz.; Mexico (Sinaloa, Sonora).

In the flora area, Solanum lumholtzianum is found only in Pima and Santa Cruz counties.