Rubber vine (
Cryptostegia grandiflora) is a highly invasive perennial woody shrub or vine. It is native to Madagascar, but widely distributed throughout tropical and subtropical regions worldwide. There have been many documented cases of toxicity in horses across Australia, as a result of ingestion of rubber vine.
What does rubber vine look like?
- Height: C. grandiflora can grow unsupported 1-2 m high, or it can scramble up to 30m high in trees.
- Stems: It has grey-brown stems that are covered in raised spots.
- Leaves: It's leaves are thick , leathery, glossy dark green on the top surface and pale and dull on the bottom.
- Flowers: It's flowers bloom primarily in the summer, producing white, purple or pink colored tube-shaped flowers.
- Fruit/Seeds: Green or brown pairs of pod-like fruits containing flat brown seeds are formed between the summer and late autumn months.
C. grandiflora stems, leaves and unripe seed pods exude a white, milky sap when broken or cut.
What toxins does rubber vine contain?
All parts of rubber vine contain cardiac glycosides, in both dry or fresh form. Cardiac glycosides inhibit the cellular Na+/K+-ATPase which enhances cardiac inotropy (contractility) and slows the heart rate. Horses are particularly susceptible to poisoning by this plant.
