Pearl or netted milkvine, green milkweed vine

Gonolobus reticulatus Engelmann ex A. Gray, Proc. Amer. Acad. Arts 12: 75. 1876

Vines, herbaceous. Stems 1–5, twining, 30–200 cm, densely hirsute with long eglandular and inconspicuous glandular trichomes. Leaves with 0–1 colleter on each side of petiole; petiole 1–6 cm, densely hirsute with long eglandular and inconspicuous glandular trichomes; blade ovate, 2–10 × 1.5–7 cm, base deeply cordate, basal lobes rarely overlapping, with 2–4 laminar colleters, apex acute, surfaces hirsute with long eglandular and inconspicuous glandular trichomes abaxially, sparsely hirsute with eglandular trichomes adaxially. Inflorescences solitary, umbelliform to racemiform, extra-axillary, pedunculate, 3–10-flowered; peduncle 1–7 cm, hirsute with long eglandular and inconspicuous glandular trichomes. Pedicels 12–25 mm, hirsute with long eglandular and inconspicuous glandular trichomes. Flowers: calyx lobes spreading, lanceolate, 3–3.5 mm, apex acute, hirsute with long eglandular and inconspicuous glandular trichomes; corolla pale green with darker green reticulations on lobes, rotate, tube 1.5–2 mm, lobes spreading, broadly ovate to nearly orbiculate, 4–5 mm, hirsute with long eglandular and inconspicuous glandular trichomes abaxially, glabrous adaxially; corona united to column near base, a low, undulate-erose ring, yellow, 0.5–0.7 mm, not reaching one-half of the height of the style, glabrous; apical anther appendages silvery, reflective, deltoid, covering more than 50% of style apex; style apex nearly round, flat to broadly convex. Follicles sometimes striate, lance-ovoid to fusiform, somewhat thickened near base, 8–15 × 1.5–2 cm, apex acuminate, sparsely to moderately muricate, glabrate. Seeds brown, ovate, 9–10 × 5–9 mm, margins winged, chalazal end entire, faces rugulose; coma 3–4 cm.

Flowering Mar–Sep(–Nov); fruiting May–Feb. Hills, slopes, ridges, canyons, streamsides, limestone, granite, caliche, rocky, sandy, and clay soils, juniper-oak and riparian woodlands, thornscrub; 0–1500 m; Tex.; Mexico (Chihuahua, Coahuila, Guanajuato, Nuevo León, Querétaro, San Luis Potosí, Tamaulipas).

Matelea reticulata co-occurs with the similar M. edwardsensis but is more common, more wide­spread, and more ecologically labile than that species. Characters distinguishing these species are discussed under 14. M. edwardsensis. The reflective apical anther appendages of M. reticulata are unusual among the milkweeds of the flora region, and their role in pollin­ator attraction seems important but is unstudied. The species is quite uncommon and sporadic west and south of the Edwards Plateau.