Hairy clustervine

Ipomoea tamnifolia Linnaeus, Sp. Pl. 1: 162. 1753; Thyella tamnifolia (Linnaeus) Rafinesque

Vines, annual. Herbage hairy, hairs usually simple, sometimes 2-armed, white, becoming ferruginous dry. Stems erect, strongly climbing, or trailing, 1–4 m, often flowering when a few dm tall. Leaf blades ovate, 20–160 × 10–120 mm, base cordate, margins slightly repand, apex acuminate to attenuate. Inflorescences dense, capitate, 6–20+-flowered, densely hirsute, bracts foliaceous, densely hairy, hairs simple, white, ferruginous dry. Flowers: sepals subequal or outers longer than inners, lanceolate to lance-linear, 8–10 mm, abaxial surface hirsute or sericeous; corolla blue, funnelform, 9–15 mm, limb entire or 5-angled. Capsules subglobose, 4–6 mm. Seeds 2–2.8 mm, outer 2 margins wingless or each with a very narrow ridge. 2n = 18.

Flowering Aug–Feb. Disturbed sites, dry stream beds, fields, roadsides, swamps; 0–200 m; Ala., Ark., Fla., Ga., Ill., La., Miss., Mo., N.Y., N.C., Ohio, Okla., Pa., S.C., Tenn., Tex.; Mexico; West Indies; Central America; South America; Africa.

Within the flora area, Jacquemontia tamnifolia is most abundant in the southeastern United States; waif outliers are known from other states. It is the most wide­spread species in Jacquemontia. Because it is wide­spread and invasive in both the Old World and New World subtropics and tropics, it is uncertain where it is native and introduced.