Funastrum bilobum, with no English name though species of Funastrum often are referred to as climbing milkweeds and twinevines, is a climbing subshrub native to Mexico, Central America and Venezuela. It belongs to the familyApocynaceae.
Description
The following field marks helping to distinguish Funastrum bilobum from similar species:
Its climbing stems are almost entirely hairless. When injured, plant parts issue a milky latex.
Leaves have petioles up to 4.5cm (1+3⁄4in) long, and blades which generally are heart-shaped and up to 8cm (3+1⁄4in) long and 5cm (2in) wide, with pronounced backward-directed lobes at the bases. Blade undersides are paler than the upper surfaces.
Umbel-type inflorescences may bear more than 40, densely grouped flowers on hanging peduncles about 6cm (2+1⁄4in) long.
Flowers have slender pedicels up to 5cm (2in) long. Their hairy, sharp-pointed sepals are about 2mm (1⁄16in) long and the pale green, backward-pointed petals are about 9mm (3⁄8in) long. The 5 plump, scoop-shaped "hoods" of the "corona" surrounding the greenish gynostegium are white and up to 3.4mm (1⁄8in) tall. Below the hoods a disc or ring encircles the gynostegium up to 1.1mm (1⁄16in) thick.
Follicle-type fruits up to 10.6cm (4+1⁄4in) long and 2.6cm (1in) wide are asymmetrically broad in the middle and taper at both ends (fusiform). Generally they are smooth-skinned with modest ribs. Seeds up to 6.7mm (1⁄4in) long and about half as wide are somewhat warty, the margins have no indentations, and the tufts of white trichomes, the "comas" atop them, are up to 3.5cm (1+3⁄8in) tall.
Distribution
In Mexico, Funastrum bilobum occurs in approximately the southern half of the country, including the Yucatan Peninsula. It is found in all Central American countries, and in northern South America in Colombia and Venezuela.
Habitat
Funastrum bilobum occurs in gallery forest associated with bodies of water, tropical forests of various types, dry scrubland and habitats disturbed by humans at elevations, below 1,175m (3,855ft). Images on this page show an individual encountered draped over a stone wall in a village in Mexico's Yucatán state.
Ecology
The violet sabrewing hummingbird, Campylopterus hemileucurus, has been documented interacting with Funastrum bilobum.
Conservation status
With a wide distribution and ability to survive in disturbed environments, a preliminary study considered Funastrum bilobum to be of least concern (LC) under the IUCN Red List criteria.
In traditional medicine
In Mexico's state of CampecheFunastrum bilobum is used for pimples and snakebite. The milky latex is used. Immediately after a snakebite the leaves are chewed and the milky latex is swallowed.
Earlier works included the similar Funastrum lindenianum and Funastrum refractum within the concept of Funastrum bilobum but now are considered distinct species.
Etymology
The genus name Funastrum derives from the Latin funis, meaing means "rope" and the suffix astrum, which means "star" or "similar". The name refers to the ropy, twining stems of species in the genus, and their flowers' vague similarity to 5-pointed stars.
The bi- in the species name bilobum was taken into English around the 1500s and comes from the French of that time. The meaning of "two" possibly is based partly on or influenced by the Latin bini meaning "twofold". The -lobum is based on the Late Latin lobus, which is derived from the Greek lobos, meaning "lobe". Thus "two lobed", possibly referring to the two-lobed leaf bases.
↑Hassler, Michael (May 20, 2026). "Funastrum bilobum (Hook. & Arn.) J.F.Macbr". Synonymic Checklist and Distribution of the World Flora. Version 26.05. Germany: World Plants. Retrieved July 15, 2026.
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