// SPECIES PROFILE · VINE · NATIVE · WOODLAND EDGE

Angular-fruit Milkvine

Matelea gonocarpos

Angular-fruit Milkvine is one of the more unusual and underappreciated native vines in the NE Oklahoma flora — a twining, herbaceous plant in the milkweed subfamily (Asclepiadoideae) with heart-shaped leaves, star-shaped greenish-brown flowers with a peculiar central fleshy disk, and distinctive angular, warty seed pods that split to release tufted seeds. Matelea gonocarpos (formerly M. gonocarpa) is a close relative of milkweeds and shares their milky sap and chemical defenses, making it a larval host for milkweed tussock moths and other specialist insects that have evolved to handle the toxic cardenolides. In NE Oklahoma, it clambers through rich woods, thickets, and bottomlands in the eastern Cross Timbers and Ozark margins. This is not a vine for the formal garden — the flowers are subtle and strange rather than showy — but for the native plant enthusiast or ecological gardener, it is a fascinating and conversation- worthy addition to a woodland edge or shaded arbor.

// QUICK FACTS

Family: Apocynaceae (dogbane family) — subfamily Asclepiadoideae (milkweed)
Life cycle: Herbaceous perennial vine; dies back to ground in winter
Native range: Southeastern & south-central US — Virginia to Florida, west to Texas and eastern OK
USDA hardiness: Zones 5–9 (Tulsa = 7a/7b)
Mature size: 6–12 ft climbing; herbaceous, twining
Bloom: May–July (NE OK)
Flower: Star-shaped, greenish-brown, five petals, central fleshy disk
Sun: Part shade to full shade
Soil: Moist, rich, well-drained woodland soil
Water: Medium; consistent moisture preferred
Wildlife: Milkweed tussock moth host · pollinated by flies & beetles
Fruit: Distinctive angular, warty seed pods with tufted seeds

Angular-fruit Milkvine (Matelea gonocarpos) with heart-shaped leaves and unusual flowers — *Matelea gonocarpos* — twining vine with heart-shaped leaves, unusual star-shaped flowers, and distinctive angular seed pods. Photo: Rooted Revival.

Identification

Habit & Leaves

Slender, twining, herbaceous perennial vine 6–12 ft, dying back to the ground each winter. Stems contain milky white latex when broken. The leaves are opposite, heart-shaped (cordate), 2–5 in long, with entire margins, smooth to slightly hairy surfaces, and long petioles. The foliage is soft and medium green.

Flowers

The flowers are unlike anything else in the garden: five-petaled, star-shaped, greenish-brown to purplish-brown, about 1–1.5 in across, with a prominent central fleshy disk (corona) that is characteristic of the milkweed subfamily. The color and scent (sometimes described as fetid or mushroom-like) attract flies and beetles as primary pollinators. Blooms appear from May through July at the leaf axils.

Fruit

The fruit pods are the most distinctive feature: angular, strongly ridged or warty follicles 3–5 in long, covered with soft, finger-like projections, splitting along one side to release tufted seeds with silky coma (like miniature milkweed fluff) that are wind-dispersed. The pods are pale green maturing to brown and persist on the vine into fall.

Habitat & Range in NE Oklahoma

Matelea gonocarpos is found in rich, moist woods, bottomlands, thickets, and shaded stream banks in the eastern Cross Timbers and Ozark foothills of NE Oklahoma. It requires partial to full shade and consistently moist, well-drained woodland soil. It is uncommon in cultivation but worth seeking out from native plant nurseries.

Ecology & Wildlife Value

Lepidoptera Host

As a member of the milkweed subfamily, Matelea contains cardiac glycosides (cardenolides) in its milky sap, making it toxic to most herbivores. Specialized insects that have evolved tolerance to these compounds, including the milkweed tussock moth (Euchaetes egle) and potentially monarch butterfly relatives, may use Matelea species as host plants. The plant also hosts milkweed bugs (Oncopeltus fasciatus) and oleander aphids (Aphis nerii), both specialized milkweed herbivores.

Pollination

The unusual greenish-brown flowers with their central fleshy disk are adapted for fly and beetle pollination (sapromyophily) — the color and sometimes fetid scent mimic carrion or fungi to attract these pollinators. Small flies and nitidulid beetles are the primary visitors.

Horticulture & Care

Site selection

Milkvine needs partial to full shade and consistently moist, humus-rich, well-drained woodland soil. It is a natural for a shaded arbor, woodland garden, or the dappled shade under mature hardwoods. Provide a small trellis, shrub, or fence for the vine to climb.

Planting & Maintenance

Plant container-grown stock in spring. Plants are rarely available commercially; source from native plant specialty nurseries.
Apply 2–3 in of leaf litter mulch to retain moisture.
Water consistently during establishment and dry spells.
Cut back dead stems in late winter before new growth emerges.
This vine is not aggressive and requires no containment.

Companion planting

Plant in a woodland garden alongside Spicebush, Wild Ginger, Maidenhair Fern, and Woodland Phlox for a layered woodland understory.

Photo Reference

Sources & Further Reading

USDA NRCS PLANTS Database — Matelea gonocarpos: plants.usda.gov/plant-profile/MAGO2
Lady Bird Johnson Wildflower Center: wildflower.org — MAGO2