1. Heliotropium amplexicaule Vahl (clasping heliotrope)

H. anchusifolium Poir.

Map 1902

Plants perennial herbs, with a deep, woody root. Stems 30–45 cm long, ascending, sometimes from a spreading base, finely hairy, with some or most of the hairs gland-tipped. Leaves alternate, sessile. Leaf blades 2–7 cm long, 5–20 mm wide, herbaceous (not succulentt), narrowly oblong-elliptic to oblanceolate, tapered at the base, angled or tapered to a bluntly or sharply pointed tip, the margins entire or more often somewhat wavy, the surfaces sparsely to moderately hairy. Inflorescences terminal clusters of 2–5 scorpioid spikes on a stalk 2–3 cm long, the spikes densely flowered, lacking bracts. Calyces 2–3 mm long, the lobes lanceolate, pubescent with both bristly hairs and smaller gland-tipped hairs, spreading after the fruit has dispersed. Corollas 6–7 mm long, 5–6 mm in diameter (measured across the spreading lobes), funnel-shaped to trumpet-shaped, blue, purple, or rarely white, hairy on the outer surface, the tube 3–4 mm long, hairy toward the tip on the inner surface, the lobes 1–2 mm long. Stamens attached at the base of the tube, the anthers 1.0–1.2 mm long. Stigma sessile, the sterile appendage broadly obconic, rounded to bluntly pointed at the tip, hairy. Fruits 2.5–3.0 mm long, 2–3 mm wide, depressed-globose to broadly ovoid, shallowly lobed at the tip, glabrous, eventually splitting into 2 nutlets (each 1- or 2-seeded). Nutlets with the dorsal surface roughened and finely wrinkled, brown. 2n=26, 28. July–August.

Introduced, known thus far only from a single historical collection from the city of St. Louis (native of South America, introduced in the eastern [mostly southeastern] U.S. and California) Disturbed areas.

This species is commonly cultivated as an ornamental in gardens, mostly as an annual in Missouri’s climate.