5. Solanum elaeagnifolium Cav. (white horse nettle, silverleaf nightshade)

Pl. 566 h–j; Map 2640

Plants perennial herbs (sometimes somewhat woody at the base), with deep, long-creeping rhizomes. Stems 15–70(–100) cm long, erect or strongly ascending, unbranched or with few to several, ascending branches, densely pubescent with stellate, nonglandular hairs (these a mixture of sessile and short-stalked, with 9–13 branches), the green tissue totally obscured by the densely matted, silvery-white hairs; unarmed or more commonly armed with scattered, slender, straight, tan to orangish brown prickles 1–4 mm long. Leaves unarmed or with scattered, short prickles, mostly along the petiole and midvein, mostly short-petiolate, the petiole unwinged, densely stellate-hairy, the hairs sessile, with 9–13 branches). Leaf blades 3–10(–15) cm long, simple, narrowly lanceolate to oblong-lanceolate or narrowly oblong, angled to a bluntly or sharply pointed tip, obliquely rounded to more commonly tapered at the base, the margins entire or shallowly to moderately wavy, the surfaces densely pubescent with stellate hairs, the green tissue totally obscured by the densely matted, silvery-white hairs. Inflorescences axillary near the stem tips, sometimes appearing terminal, of solitary flowers or more commonly racemes (short, often appearing clustered at flowering, the axis with sparse to moderate, short prickles, pubescent similar to the stems, elongating as the fruits develop) of 3–7 flowers, the flower stalks not jointed, slender to moderately stout, thickened toward the tip. Flowers spreading to ascending, the stalks often becoming more or less nodding as the fruits develop. Calyces 9–14 mm long at flowering, the tube somewhat 5-angled at flowering, not or only slightly enlarged at fruiting, the tube spreading or only loosely cupping the base of the fruit, deeply 5-lobed at flowering, the lobes as long as to longer than the tube, slightly unequal, linear above a triangular base, the outer surface unarmed or with only scattered small prickles toward the base, also densely stellate-hairy. Corollas 10–16 mm long, purple to bluish purple or lavender (rarely white elsewhere), lobed to at or above the midpoint, the lobes broadly ovate-triangular, sometimes appearing minutely wavy or irregular along the margins, tapered abruptly to bluntly or sharply pointed tips, spreading at flowering, the inner surface glabrous, the outer surface stellate-hairy. Anthers equal, 6–9 mm long, narrowly oblong (slightly tapered toward the tip), yellow, dehiscing by terminal pores. Ovary 2-locular, the surface stellate-hairy, the style slightly exserted from the anther ring. Fruits 1.0–1.5 cm long, globose, lacking stony granules, yellow (eventually turning black with age), dull to somewhat shiny, unarmed, glabrous or sparsely stellate-hairy. Seeds 3–5 mm in longest dimension, broadly ovate to broadly oblong in outline, sometimes bluntly angular, moderately flattened, unwinged, the surface smooth or very slightly few-wrinkled, brown to dark brown or grayish brown, dull or somewhat shiny. 2n=24, 72. July–September.

Uncommon, mostly in the western half of the state (Missouri and Kansas south to Texas and Arizona; Mexico; introduced farther east and west). Glades, upland prairies, tops of bluffs, and margins of salt springs; also pastures, railroads, roadsides, and open, disturbed areas.