Herbs, annual, spreading, sparsely to moderately armed, 0.3–0.8 m, prickles yellowish, straight, needlelike, 3–7 mm, sparsely to densely pubescent, hairs short, unbranched, glan­dular, occasionally with a few longer, unbranched, eglandular hairs, abaxial leaf surfaces usually also with sessile to short-stalked, few-rayed, stellate hairs, central ray equal to or longer than lateral rays. Leaves petiolate; petiole 2–7 cm; blade simple to compound, broadly ovate, 4–10(–15) × 3–8 cm, margins bipinnately lobed or divided with 3–4 main leaflets per side, these with obtuse or rounded lobes, base truncate. Inflorescences extra-axillary, unbranched, 4–10-flowered, 3–11 cm. Pedicels 1–2 cm in flower, 1–2 cm and erect in fruit. Flowers bilaterally sym­metric; calyx accrescent and tightly covering fruit, densely prickly, 2.5–3.8 mm, densely glandular-pubescent, lobes linear-lanceolate; corolla violet or blue, pentagonal-stellate, 2.5–3.5 cm diam., with interpetalar tissue at margins and bases of lobes; stamens unequal, lowermost much longer and curved; anthers narrow and tapered, dehis­cent by terminal pores, short anthers yellow, 6–10 mm, longer anther purplish, 11–16 mm; ovary glabrous. Berries brown, globose, 0.8–1.2 cm diam., glabrous, dry, without sclerotic granules. Seeds dark brown, flat­tened, 2.3–3 × 2–2.5 mm, reticulately wrinkled, ridged, or undulate. 2n = 24.

Distribution

sc, se United States, Mexico.

Discussion

North American plants identified as Solanum heterodoxum Dunal are largely misidentifications of S. citrullifolium. Solanum heterodoxum in the current sense is now restricted to Mexico.

Varieties 2 (2 in the flora).

Selected References

None.

Lower Taxa

Solanum citrullifolium var. citrullifolium, Solanum citrullifolium var. setigerum

Key

1	Stems scattered-prickly with fewer than 20 prickles per cm of stem; prickles often to 1 mm diam. at base; stems densely glandular-pubescent.	Solanum citrullifolium var. citrullifolium
1	Stems densely bristly with 25+ bristles per cm of stem; bristles mostly less than 0.5 mm diam. at base; stems sparsely glandular-pubescent.	Solanum citrullifolium var. setigerum