The brown, starlike, spreading flowers of oldfield milkvine, a climbing milkweed, differ from those of other milkweeds, but milky sap, warty pods with silk-tasseled seeds, and the structures in the center of the flowers show its true alliance.
Oldfield milkvine is a climbing or trailing perennial vine with milky sap.
The flowers are brownish purple, like a 5-pointed star, with spreading corolla lobes ½–¾ inch long; the flower clusters arise on stalks from the leaf axils.
Blooms May–June.
The leaves are opposite, broadly ovate and heart-shaped, to 6 inches long.
The fruit is a narrow pod, to 4 inches long, covered with slender, warty projections.
Similar species: There are a few other climbing milkweeds that occur in Missouri.
- Baldwyn's milkvine (Matelea baldwyniana), with whitish (not brownish purple) corolla lobes, is scattered in southwestern Missouri.
- Angle-pod (Gonolobus suberosus), found mostly in the Bootheel, resembles Mateliea species vegetatively but has yellowish flowers and angled (ridged) pods without warty projections.
- Sand vine (Cynanchum laeve) has clear, not milky sap, and tiny flowers with upright, not spreading corolla lobes.
Stem length: to nearly 10 feet.
Scattered to common, mostly south of the Missouri River.
Habitat and Conservation
Occurs in glades, savannas, tops of bluffs, rocky, open upland forests, and along streams and rivers. Less common in bottomland forests. Also found along roadsides.
Status
Native Missouri nonwoody climbing vine.
Human Connections
This native vine can be trained on a trellis or fence, where it will attract butterflies.
In Illinois and Maryland, this species is listed as endangered; in Maryland, it is probably extirpated. Loss of habitat is probably the cause.
Ecosystem Connections
Butterflies and other insects are attracted to the flowers.
A vining habit enables a plant to use another plant or structure as a support, so it can reach higher, towards the sun and pollinators, without expending resources to develop a stout stem or trunk.
The entire former milkweed family (Asclepiadaceae) has recently been rolled into the dogbane family (Apocynaceae). For many years, botanists have known the two families were closely related. The milkweed group, with its distinct floral structures, is still considered a unique subfamily or tribe of the dogbane family. As you consult various sources, you can expect to see milkweeds grouped in either family.
