Trans-Pecos or Texas milkvine

Vines, herbaceous (rarely suffru­tescent without corky bark). Stems 1–5(–10), twining (at least at stem tips), 30–100 cm, short-hirsute with spreading to retrorse eglandular and minute glandular trichomes. Leaves with 1 or 2 colleters on each side of petiole; petiole 0.8–3.5 cm, short-hirsute with eglandular and minute glandular trichomes; blade deltate to ovate, 2–7.5 × 1–4.5 cm, base deeply cordate, with 2–4 laminar colleters, apex long-acuminate, surfaces densely hirsute, eglandular. Inflorescences simple (rarely paired), umbelliform to somewhat racemiform, extra-axillary, pedunculate, 1–6-flowered; peduncle 0.3–1.2 cm, short-hirsute with eglandular and minute glandular trichomes. Pedicels 3–10 mm, short-hirsute with eglandular and minute glandular trichomes. Flowers: calyx lobes ascending, lanceolate, 2–3 mm, apex acute, short-hirsute with eglandular and minute glandular trichomes; corolla green, not or obscurely reticulate, tubular-campanulate, densely hirtellous, tube 1.5–2.5 mm, lobes spreading, 4–6 mm; corona concealed in throat, a ring with 5 trun­cate lobes, each with an adaxial incurved appendage incumbent on backs of anthers, green to cream, 1–1.5 mm, glabrous; apical anther appendages cream, deltoid; style apex green, pentagonal, flat. Follicles gray-striate, fusiform, 9–14 × 2–2.5 cm, apex acuminate, smooth, glabrous. Seeds brown, ovate, 8–11 × 4–5 mm, margins thickly winged, chalazal end minutely erose, faces smooth; coma 3–4 cm.

Flowering May–Oct; fruiting Jul–Oct. Hills, slopes, arroyos, rocky igneous soils, juniper grasslands; of conservation concern; 1200–1800 m; Tex.

Endemic to the Big Bend region, Matelea texensis is known only from a few sites in Brewster County, south of Alpine. It is likely that some populations have been lost to road widening. Matelea texensis is most similar to M. producta, from which it differs by densely hirtellous corollas.