Closely related to Cryptostegia madagascariensis, and often confused with it[
Nerium grandiflorum (Roxb. ex R.Br.) Roxb.
Common Name: India Rubber Vine
Cryptostegia grandiflora is an evergreen climbing shrub, scrambling over the ground and climbing into nearby plants, supporting itself by means of its slender, twining stems. Older plants can climb 20 - 30 metres into the forest canopy[
The plant has, in the past, been utilized and occasionally cultivated, for the fibre and latex that can be obtained from the stems[
]. Since the advent of synthetic rubber it is no longer considered to be of value. The plant is often cultivated as an ornamental in tropical areas, valued especially for its large, showy flowers[
The plant contains glucosides that interfere with heart function; ingestion will also provoke stomach and intestinal upset[
]. In Madagascar the plant has reportedly been used for criminal purposes and as a poison for vermin. The powdered leaves, mixed with water, when swallowed can cause persistent vomiting after half an hour; followed by death within 15 hours[
Although Cryptostegia grandiflora is highly poisonous, it is extremely unpalatable and thus grazing animals usually avoid it[
Africa - southern and southwestern Madagascar.
Growing into the canopy of riverine forests, it is also found as a sprawling shrub along gullies, creeks, as well as disturbed areas such as roadside ditches where run-off water accumulates, around waterholes and at the edge of coastal salt marshes[
|Other Uses Rating||
|Cultivation Status||Cultivated, Ornamental, Wild
Cryptostegia grandiflora is a plant of the dry south-west of Madagascar where annual rainfall is less than 600mm and as low as 300 mm, at an elevation below 600 metres. The plant is known to tolerate rainall to 1,800mm in cultivation. The dry season lasts at least 8 months, but droughts of 12 - 18 months are not uncommon[
]. Frosts are unknown.
Succeeds in a sunny position in a moist but well drained soil[
Cryptostegia grandiflora is a highly invasive weed in semi-arid natural ecosystems, especially dry or monsoonal rainforest. It has the potential to spread much further, especially in Australia where it poses a threat to national parks and has been declared a noxious weed. It is now a common and highly invasive component of dry rain forest and of the fringing riverine vegetation, as well as on flood plains from where it invades grazing land; mainly in the tropical to subtropical 500 - 1,400mm annual rainfall zone. The historical evidence suggests that there is a significant lag period before the plant assumes an invasive status. Thus, those countries where the plant has been cultivated as an ornamental or as a crop, but where it has not yet become invasive, are at future risk of invasion[
New shoots can elongate rapidly during favourable conditions, which can result in long, unbranched stems up to 5 metres long being produced[
The robust roots can penetrate 12 metres into the soil, producing yellow, fibrous feeding roots[
The leaves and the latex are used to treat fungal infections and heart problems[
]. Extreme caution is advised, see notes above on toxicity.
The plant can be pruned and grown as a hedge[
A latex obtained from the stems can be used to make rubber[
]. It is equal in quality to the latex obtained from the rubber tree, Hevea sp.[
]. Very difficult to obtain by tapping[
]. A reasonably high-quality rubber is obtained from the latex[
]. The plants of this genus abound in a milky juice, which, when exposed for a short time to the sun,
is converted into pure caoutchouc[
A fibre is obtained from the stems[
]. Said to be a fine, strong fibre, resembling flax. which may be spun into the finest yarn[
Seed - usually germinates well if sown soon after ripening, but can lose viability within the first 12 months if the seed is not stored dry at temperatures of around 5°c[
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