Alabama milkvine or spinypod

Vincetoxicum alabamense Vail, Bull. Torrey Bot. Club 30: 178, plate 9. 1903; Cyclodon alabamensis (Vail) Small

Vines, herbaceous. Stems 1–5, twining, 20–150 cm, hir­sute with eglandular and incon­spicuous glandular trichomes. Leaves with 0–2 colleters on each side of petiole; petiole 1–5 cm, hirsute with eglan­dular and inconspicuous glandular trichomes; blade ovate to nearly orbiculate, 4–12 × 2–10 cm, base shal­lowly to deeply cordate, with 0–2(–4) laminar colleters, apex acute to acuminate, surfaces hirsute with eglan­dular and inconspicuous glandular trichomes. Inflores­cences solitary, umbelliform, extra-axillary, pedun­culate, 1–5-flowered; peduncle 0.2–1.2 cm, hirsute with eglan­dular and inconspicuous glandular trichomes. Pedicels 5–15 mm, hirsute with eglandular and inconspicuous glandular trichomes. Flowers: calyx lobes spreading, elliptic, 1.9–3.4 mm, apex acute, hir­sute with eglandular and inconspicuous glandular trichomes; corolla dark green abaxially, creamy yellow to pale green with dark green reticulations, with a deep yellow ring at base of corona adaxially, very widely rotate-campanulate, tube 0.5–1.5 mm, lobes spreading, plane, ovate, 7–10 mm, glabrous abaxially, hirtellous adaxially at base of lobes; corona united to column near base, a saucer-shaped ring with small apical teeth and 5 pointed lobes, greatly exceeded by style apex, appressed to stamens, deep yellow, 0.5–1 mm, glabrous; apical anther appendages bright white with green patch at base, ovate, covering more than 50% of style apex; style apex yellow, pentagonal, flat. Follicles not striate, lance-ovoid to ovoid, 4.9–8 × 1.5–2.5 cm, apex acuminate, densely muricate, minutely hirsute. Seeds tan to brown, broadly ovate, 7–9 × 6–8 mm, margins broadly winged, chalazal end scarcely erose, faces rugulose; coma 3.5–4 cm.

Flowering (Mar–)Apr–Jun; fruiting Jun–Dec. Sandy oak-hickory and mixed hardwoods on ravine slopes; of conservation concern; 10–100 m; Ala., Fla., Ga.

Matelea alabamensis is distributed on the Gulf Coastal Plain from the Choctawhatchee to the Chattahoochee-Apalachicola watersheds. It is uncommon and restricted to a handful of populations in Dale and Henry counties in Alabama; Gadsden, Liberty, Walton, and Washington counties in Florida; and Clay and Early counties in Georgia. A report from southeastern Georgia has not been confirmed and is doubtful. The species has experi­enced significant habitat loss and degradation resulting in serious concerns for conservation across its range. The greenish flowers with darker reticulations and densely muricate follicles are an unusual trait combination that is unique among the spinypods of the Gulf Coast.

Matelea alabamensis is in the Center for Plant Conservation’s National Collection of Endangered Plants.