Solanum nigrescens
Solanum elaeagnifolium
divine nightshade
horse nettle, silver-leaf nightshade, white horse-nettle
petiolate;
petiole 0.5–2 cm;
blade simple, ovate to ovate-elliptic, 4–10.5 × 2–5 cm, margins entire or shallowly sinuate-dentate, base decurrent.
petiolate;
petiole 1–5 cm;
blade simple, lanceolate to oblong, 5–15 × 0.5–3 cm, margins undulate, subentire to sinuate or shallowly lobed, lobe margins entire, base truncate to cuneate.
extra-axillary or leaf-opposed, unbranched, umbel-like to racemelike, (2–)5–10-flowered, 1–3.5 cm.
extra-axillary, unbranched, 3–5(–7)-flowered, 3–5 cm.
spreading and 0.5–1 cm in flower, spreading and 1–1.5 cm in fruit.
1–3 cm in flower, reflexed and 1–3 cm in fruit.
radially symmetric;
calyx not accrescent, unarmed, 1–2 mm, sparsely pubescent, lobes deltate;
corolla white, rarely purplish, often with green or purplish central star, stellate, 1–1.5 cm diam., with sparse interpetalar tissue;
stamens equal;
anthers ellipsoidal, 2–3 mm, dehiscent by terminal pores that open into longitudinal slits;
ovary glabrous.
radially symmetric;
calyx not accrescent, unarmed or with sparse prickles, 5–10 mm, densely silvery-stellate-pubescent, lobes linear-lanceolate;
corolla pale to deep blue or violet, rarely white, pentagonal-stellate, 2–3(–3.5) cm diam., with abundant interpetalar tissue;
stamens equal;
anthers narrow and tapered, 6–9 mm, dehiscent by terminal pores;
ovary glabrous to densely stellate-pubescent.
dull green or purplish, globose, 0.5–0.8 cm diam., glabrous, with (4–)5–6(–13) sclerotic granules.
yellow to orange, drying brown or black, globose, 0.5–1.5 cm diam., glabrous, without sclerotic granules.
tan, flattened, 1.2–1.5 × 1–1.1 mm, finely pitted.
yellowish, flattened, 3–5 × 2–4 mm, minutely pitted.
= 24.
= 24, 48, 72.
Solanum nigrescens
Solanum elaeagnifolium
Solanum nigrescens is widespread in Central and northern South America and the Caribbean and extends northward into the southeastern United States along the Gulf Coast and slightly inland. Where sympatric with S. americanum, it can be distinguished by its longer anthers and dull green or purplish berries with appressed to spreading calyx lobes. Plants collected as weeds in rice and sugarcane fields of Louisiana and provisionally identified as the Chinese species S. merrillianum T. N. Liou are somewhat intermediate between S. americanum and S. nigrescens and could represent recent hybrid populations (S. Knapp et al. 2019). Solanum nigrescens differs from S. douglasii in its shorter anthers and longer filaments relative to anther length; moreover, S. douglasii is usually found west of the Rocky Mountains, whereas S. nigrescens occurs in the southeastern United States. The ranges of S. nigrescens and S. interius overlap (for example, in Texas). Solanum nigrescens may be distinguished from S. interius by its usually acute calyx lobes, smaller seeds, and more numerous sclerotic granules in the fruits. Solanum nigrescens differs from S. nigrum in its more slender peduncles and pedicels, smaller seeds, and fruits with sclerotic granules.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
Solanum elaeagnifolium has a disjunct native distribution. It occurs in arid regions of the southwestern United States and Mexico and also in Argentina, Chile, Paraguay, and Uruguay. North American plants are diploid, whereas those in Argentina are diploid, tetraploid, or hexaploid. It is invasive and considered a noxious weed in 21 states in the flora area as well as in many tropical and subtropical regions worldwide. It is toxic to livestock and can form large, rhizomatous patches that are difficult to eradicate.
A white-flowered form has been recognized as Solanum elaeagnifolium forma albiflorum Cockerell.
(Discussion copyrighted by Flora of North America; reprinted with permission.)
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