Cynanchum ovalifolium is a perennial, twining vine belonging to the milkweed family, Apocynaceae. It is one of many species within the diverse Cynanchum genus.
Botanical Characteristics
The plant’s slender stems typically do not exceed two centimeters in diameter. Twigs, petioles, and leaves produce a milky exudate. Its simple leaves grow oppositely along the stem.
Leaf blades are elliptic to obovate or ovate-oblong to lanceolate, measuring approximately 7 to 11 centimeters long and 4.5 to 6 centimeters wide. Petioles, the stalks attaching the leaf blade to the stem, are about 2.5 to 4 centimeters long. A distinguishing feature is the presence of a pair of reduced leaves or stipule-like structures often found in the axil of one leaf of each pair.
Cynanchum ovalifolium produces umbelliform inflorescences, where flowers are arranged in umbrella-like clusters. These are white, five-stellate flowers that bloom typically from July to September. The corolla lobes, which are the petals, are narrowly triangular, about 7 millimeters long, and usually twisted towards the apex.
The fruits are inflated, soft, and spongy, measuring around 11 by 4.5 centimeters, appearing green or yellowish when mature. These fruits are follicles, a type of dry fruit that splits open along one seam to release seeds. The pyriform seeds, approximately 12 by 8 millimeters, possess white plumes about 30 to 35 millimeters long, aiding in wind dispersal.
Habitat and Distribution
Cynanchum ovalifolium is found across a broad geographical range, primarily in Malesia and Asia, including India and Australia’s Cape York Peninsula. Recent records also indicate its presence in Laos, Taiwan, Borneo, Jawa, Malaya, Maluku, New Guinea, Philippines, Sulawesi, Sumatera, and Thailand.
It is commonly found in rainforests, monsoon forests, and open forest settings. This species grows at altitudes ranging from near sea level up to 300 meters, and in some instances, up to 1000 meters in brushwood, hedges, and open areas. It prefers fertile, well-drained soils and moderate sunlight, often using existing vegetation for support.
Ecological Role and Considerations
The genus name Cynanchum originates from Greek words meaning “dog” and “to choke,” leading to the common name “dog-strangling vine” for some species within this genus. C. ovalifolium is not widely known by that name.
The plant provides a food source and habitat for various insects, including pollinators like butterflies and bees. The vine also offers shelter for small animals and birds. While Cynanchum ovalifolium is not generally considered threatened, its populations can be affected by habitat loss and environmental changes.
Potential Uses and Significance
Its bitter leaves and young fruits are consumed in the Moluccas. The broader Cynanchum genus, to which C. ovalifolium belongs, has a history of use in folk medicine.
Various Cynanchum species have been traditionally employed for fever reduction, cough suppression, diuresis, and pain relief. However, specific medicinal uses for Cynanchum ovalifolium are not widely documented.