Rubber Vine
Encyclopedia
Cryptostegia grandiflora, commonly known as rubber vine, is a woody-perennial
vine
that is native to south-west Madagascar
. It is also a significant weed in northern Australia
, sometimes regarded in fact, as the worst weed
in all of Australia. It has also been introduced to most other tropical and subtropical regions by man, because of its attractive flower
s and the fact that its latex contains commercial quality rubber
(hence the name). It is now naturalised in the Caribbean, East Africa
, Mauritius
, India
, Southeast Asia
, Latin America
, the southern United States
, Fiji
and New Caledonia
.
Seeds germinate after the first rains of the wet season
, but growth does not become rapid until well after the wet season begins. However, if enough water is available, rubber vine can grow as much as five metres in one month. Flowering usually occurs after the wet season ends, along with fruit set. It is usual to find both mature and immature fruit on rubber vine at any one time.
Rubber vine seeds are dispersed by winds and flooding
. This is particularly important in Australia where very large river floods can occur.
climate. It can grow maximally on an annual rainfall of 1700 millimetres, but seeds best with an annual rainfall of 400 millimetres or less. For this reason, rubber vine thrives on (in fact, requires) the extreme variability of rainfall
and streamflow characteristic of central Queensland
. The extreme variability (four times that of other countries to which it has been introduced) is almost certainly why rubber vine has become a major weed in Australia and not any other country in which it has been introduced.
to Port Hedland in the Pilbara. It has not yet moved much beyond Queensland. It is a major threat to gallery forests along rivers in northern Australia, because it can strangle and kill the native trees by climbing over them and completely eliminating access to light. It can also do the same thing in savanna
woodlands away from watercourses. Rubber vine is also extremely toxic to all livestock: less than 10 grams of rubber vine leaves can kill a 400 kilogram horse
within six days, and it is also highly toxic to cattle, sheep and goat
s. However, it is extremely unpalatable and only causes death in dry seasons when green grass
is very scarce. It is fairly common in Indonesia.
Control of rubber vine has relied on importing biological agents from its native habitat in southwestern Madagascar, the most important of which is the "rubber vine rust
" (Maravalia cryptostegiae). In some areas near Charters Towers, this rust has infected most rubber vine plants, but its effect has not been great enough to stop the spread of the plant westwards. The "rubber vine moth" (Euclasta whalleyi) was introduced earlier than the rust (in 1988) but has not proved very effective. The extreme remoteness of most rubber vine infestations rules out mechanical and chemical control for dealing with the plant.
Perennial plant
A perennial plant or simply perennial is a plant that lives for more than two years. The term is often used to differentiate a plant from shorter lived annuals and biennials. The term is sometimes misused by commercial gardeners or horticulturalists to describe only herbaceous perennials...
vine
Vine
A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...
that is native to south-west Madagascar
Madagascar
The Republic of Madagascar is an island country located in the Indian Ocean off the southeastern coast of Africa...
. It is also a significant weed in northern Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, sometimes regarded in fact, as the worst weed
Weed
A weed in a general sense is a plant that is considered by the user of the term to be a nuisance, and normally applied to unwanted plants in human-controlled settings, especially farm fields and gardens, but also lawns, parks, woods, and other areas. More specifically, the term is often used to...
in all of Australia. It has also been introduced to most other tropical and subtropical regions by man, because of its attractive flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s and the fact that its latex contains commercial quality rubber
Rubber
Natural rubber, also called India rubber or caoutchouc, is an elastomer that was originally derived from latex, a milky colloid produced by some plants. The plants would be ‘tapped’, that is, an incision made into the bark of the tree and the sticky, milk colored latex sap collected and refined...
(hence the name). It is now naturalised in the Caribbean, East Africa
East Africa
East Africa or Eastern Africa is the easterly region of the African continent, variably defined by geography or geopolitics. In the UN scheme of geographic regions, 19 territories constitute Eastern Africa:...
, Mauritius
Mauritius
Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...
, India
India
India , officially the Republic of India , is a country in South Asia. It is the seventh-largest country by geographical area, the second-most populous country with over 1.2 billion people, and the most populous democracy in the world...
, Southeast Asia
Southeast Asia
Southeast Asia, South-East Asia, South East Asia or Southeastern Asia is a subregion of Asia, consisting of the countries that are geographically south of China, east of India, west of New Guinea and north of Australia. The region lies on the intersection of geological plates, with heavy seismic...
, Latin America
Latin America
Latin America is a region of the Americas where Romance languages – particularly Spanish and Portuguese, and variably French – are primarily spoken. Latin America has an area of approximately 21,069,500 km² , almost 3.9% of the Earth's surface or 14.1% of its land surface area...
, the southern United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, Fiji
Fiji
Fiji , officially the Republic of Fiji , is an island nation in Melanesia in the South Pacific Ocean about northeast of New Zealand's North Island...
and New Caledonia
New Caledonia
New Caledonia is a special collectivity of France located in the southwest Pacific Ocean, east of Australia and about from Metropolitan France. The archipelago, part of the Melanesia subregion, includes the main island of Grande Terre, the Loyalty Islands, the Belep archipelago, the Isle of...
.
Seeds germinate after the first rains of the wet season
Wet season
The the wet season, or rainy season, is the time of year, covering one or more months, when most of the average annual rainfall in a region occurs. The term green season is also sometimes used as a euphemism by tourist authorities. Areas with wet seasons are dispersed across portions of the...
, but growth does not become rapid until well after the wet season begins. However, if enough water is available, rubber vine can grow as much as five metres in one month. Flowering usually occurs after the wet season ends, along with fruit set. It is usual to find both mature and immature fruit on rubber vine at any one time.
Rubber vine seeds are dispersed by winds and flooding
Flood
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water...
. This is particularly important in Australia where very large river floods can occur.
Description
A rubber vine can grown up to 2 metres (m) tall as a shrub, but when it is supported on other vegetation as a vine, it can reach up to 30 metres in length. Rubber vine prefers areas where annual rainfall is between 400 and 1400 millimetres (mm), and is well adapted to a monsoonalMonsoon
Monsoon is traditionally defined as a seasonal reversing wind accompanied by corresponding changes in precipitation, but is now used to describe seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea...
climate. It can grow maximally on an annual rainfall of 1700 millimetres, but seeds best with an annual rainfall of 400 millimetres or less. For this reason, rubber vine thrives on (in fact, requires) the extreme variability of rainfall
Precipitation (meteorology)
In meteorology, precipitation In meteorology, precipitation In meteorology, precipitation (also known as one of the classes of hydrometeors, which are atmospheric water phenomena is any product of the condensation of atmospheric water vapor that falls under gravity. The main forms of precipitation...
and streamflow characteristic of central Queensland
Queensland
Queensland is a state of Australia, occupying the north-eastern section of the mainland continent. It is bordered by the Northern Territory, South Australia and New South Wales to the west, south-west and south respectively. To the east, Queensland is bordered by the Coral Sea and Pacific Ocean...
. The extreme variability (four times that of other countries to which it has been introduced) is almost certainly why rubber vine has become a major weed in Australia and not any other country in which it has been introduced.
Australia
Rubber vine is believed to have a potential range in Australia from about Coen in Cape York PeninsulaCape York Peninsula
Cape York Peninsula is a large remote peninsula located in Far North Queensland at the tip of the state of Queensland, Australia, the largest unspoilt wilderness in northern Australia and one of the last remaining wilderness areas on Earth...
to Port Hedland in the Pilbara. It has not yet moved much beyond Queensland. It is a major threat to gallery forests along rivers in northern Australia, because it can strangle and kill the native trees by climbing over them and completely eliminating access to light. It can also do the same thing in savanna
Savanna
A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...
woodlands away from watercourses. Rubber vine is also extremely toxic to all livestock: less than 10 grams of rubber vine leaves can kill a 400 kilogram horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
within six days, and it is also highly toxic to cattle, sheep and goat
Goat
The domestic goat is a subspecies of goat domesticated from the wild goat of southwest Asia and Eastern Europe. The goat is a member of the Bovidae family and is closely related to the sheep as both are in the goat-antelope subfamily Caprinae. There are over three hundred distinct breeds of...
s. However, it is extremely unpalatable and only causes death in dry seasons when green grass
Grass
Grasses, or more technically graminoids, are monocotyledonous, usually herbaceous plants with narrow leaves growing from the base. They include the "true grasses", of the Poaceae family, as well as the sedges and the rushes . The true grasses include cereals, bamboo and the grasses of lawns ...
is very scarce. It is fairly common in Indonesia.
Control of rubber vine has relied on importing biological agents from its native habitat in southwestern Madagascar, the most important of which is the "rubber vine rust
Rust (fungus)
Rusts are plant diseases caused by pathogenic fungi of the order Pucciniales. About 7800 species are known. Rusts can affect a variety of plants; leaves, stems, fruits and seeds. Rust is most commonly seen as coloured powder, composed off tiny aeciospores which land on vegetation producing...
" (Maravalia cryptostegiae). In some areas near Charters Towers, this rust has infected most rubber vine plants, but its effect has not been great enough to stop the spread of the plant westwards. The "rubber vine moth" (Euclasta whalleyi) was introduced earlier than the rust (in 1988) but has not proved very effective. The extreme remoteness of most rubber vine infestations rules out mechanical and chemical control for dealing with the plant.