Greenspot nightshade

Solanum arizonicum Parish

Herbs or shrubs, perennial, erect, unarmed, to 1.5(–3) m, sparsely to moderately pubescent, hairs white, curved, unbranched, 0.5–1 mm, eglandular. Leaves peti­olate; petiole 0.5–3(–7) cm; blade simple, ovate, 1–5(–9) × 0.5–3(–6) cm, mar­gins entire to coarsely and irregularly toothed, base truncate to acute and decurrent. Inflorescences extra-axillary or leaf-opposed, unbranched, racemelike, 2–7(–14)-flowered, 2–4 cm. Pedicels 0.5–1 cm in flower and fruit, nodding or deflexed downward in fruit. Flowers radially sym­metric; calyx not accrescent, unarmed, 2–3 mm, sparsely pubescent, lobes deltate; corolla white with yellow-green to brownish central star, stellate, 1–2 cm diam., without interpetalar tissue; stamens equal; anthers ellipsoidal and slightly tapered towards the tips, (2.5–)3–4.5 mm, dehiscent by terminal pores that open into longitudinal slits; ovary glabrous. Berries dull purplish black, globose, 0.5–1 cm diam., glabrous, with (2–)6–8 sclerotic granules per fruit. Seeds pale yellow to tan, flattened, 1.5–2 × 1–1.5 mm, finely reticulate. 2n = 24.

Flowering Mar–Nov (nearly year-round in Calif.). Dry shrubland, woodland, rocky slopes, stream banks, canyons; 0–2500 m; Ariz., Calif., N.Mex., Tex.; Mexico; West Indies (Guadeloupe); Central America (El Salvador, Guatemala, Honduras, Nicaragua).

Solanum douglasii is most commonly found west of the Rocky Mountains. It can be difficult to distinguish from S. nigrescens, but its longer, slightly tapered anthers on very short (relative to anther length) filaments is a good distinguishing character for plants in flower. The buds of S. douglasii are more pointed than those of S. nigrescens.