Hevea | |
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Hevea brasiliensis [1] | |
Scientific classification ![]() | |
Kingdom: | Plantae |
Clade: | Tracheophytes |
Clade: | Angiosperms |
Clade: | Eudicots |
Clade: | Rosids |
Order: | Malpighiales |
Family: | Euphorbiaceae |
Subfamily: | Crotonoideae |
Tribe: | Micrandreae |
Subtribe: | Heveinae |
Genus: | Hevea Aubl. |
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Range of the genus Hevea. | |
Synonyms [2] [3] | |
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Hevea is a genus of flowering plants in the spurge family, Euphorbiaceae, with about ten members. It is also one of many names used commercially for the wood of the most economically important rubber tree, H. brasiliensis . The genus is native to tropical South America but is widely cultivated in other tropical countries and naturalized in several of them. It was first described in 1775.
French botanist and explorer Jean Baptiste Christophore Fusée Aublet first described Hevea as a genus in 1775. [4] [5] [6] H. brasiliensis and H. guianensis are large trees, often reaching more than 30 m (100 ft) in height. Most of the other members of the genus are small to medium trees, and H. camporum is a shrub of around 2 m (7 ft). Trees in this genus are either deciduous or evergreen. Certain species, namely H. benthamiana, H. brasiliensis and H. microphylla, bear "winter shoots", stubby side shoots with short internodes, scale leaves on the stem and larger leaves near the tip; on these, the leaves are shed leaving the tree bare before new shoots develop. [7] The remaining species bear more vigorous side shoots which develop before the old foliage is shed and thus the tree remains green. [7] The leaves consist of three, usually elliptical, leaflets which are held horizontally or slightly drooping in most species. The inflorescences have separate male and female flowers, with the females being at the end of the panicles. The fruits are capsules, usually with three seeds, which in all except two species (H. spruceana and H. microphylla) split explosively when ripe to eject the large seeds. [7]
The genus occurs naturally in tropical South America, mostly in the Amazon basin. To the north of the basin, the land rises to the watershed of the Guiana Shield on the border between Brazil and Venezuela, and the southern foothills of these mountains form the northerly limit of the genus. It is also present in the upper reaches of the Orinoco River. The genus extends westwards as far as the foothills of the Andes and southwards to the foothills of the Mato Grosso. Its easterly limit is the Atlantic Ocean. [7] The most widespread species is H. guianensis which occurs over the whole range of the genus. [7]
The Pará rubber tree ( H. brasiliensis ) occurs mainly south of the Amazon, as does H. camporum , but the greatest diversity occurs to the north of the river, in the Rio Negro region, where all the other species occur. In this area where there are variations in soil and topography and the rainforest experiences conditions of all-year-round humidity, the genus Hevea has been undergoing a high degree of speciation. The high humidity encourages the growth of fungal leaf diseases, and the species that are deciduous avoid immediate transfer of fungal spores from old leaves onto new growth. [7] The Pará rubber tree has been introduced to and is naturalised in many tropical countries in Asia. [2] [8]
Each species has its own habitat requirements; H. brasiliensis grows on well-drained soils but tolerates light flooding; H. guianensis, H. pauciflora and H. rigidifolia grow in well-drained soil, on high river banks and on slopes; and H. camporum grows on savannahs. Other species such as H. benthamiana , H. microphylla and H. spruceana need wetter conditions in locations subject to seasonal flooding for several months each year, and H. nitida grows both in periodically inundated swamps and in drier locations such as rocky hillsides well above the flood level. [7]
The following species are recognised: [2]
Amanoa is a genus from the family Phyllanthaceae first described as a genus in 1775. It is native to South America, Central America, the West Indies, and tropical Africa.
Couroupita is a genus of flowering plants in the family Lecythidaceae first described as a genus in 1775. It is native to tropical South America and Central America.
Conceveiba is a plant genus of the family Euphorbiaceae, first described as a genus in 1775. It is native to South America and Central America.
Micrandra is a plant genus of the family Euphorbiaceae first described in 1854. It is native to South America.
Maprounea is a plant genus of the family Euphorbiaceae first named as a genus in 1775. It is native to tropical Africa, Trinidad, and tropical Central and South America.
Couratari is a genus of trees in the family Lecythidaceae, first described as a genus in 1775. They are native to tropical South America and Central America.
Acioa is a genus of plants in the family Chrysobalanaceae described as a genus in 1775. It is native to northeastern South America.
Forsteronia is a genus of plants in the family Apocynaceae, first described as a genus in 1818. It is native to South America, Central America, Mexico, and the West Indies.
Malouetia is a genus of plants in the family Apocynaceae, first described as a genus in 1844. It is native to Africa, South America, Central America, and the West Indies.
Paloue is a genus of flowering plants in the family Fabaceae. It belongs to the subfamily Detarioideae. The genera was first created with the description of Paloue guianensis by Aublet in 1775.
Amaioua is a genus of flowering plants in the family Rubiaceae. It was first described by Jean Baptiste Aublet in 1775. The genus is native to tropical America from southern Mexico to Brazil, including Cuba and Trinidad.
Couma is a genus of flowering plants in the family Apocynaceae first described as a genus in 1775. It is native to South America and Central America.
Macoubea is a genus of plant in the family Apocynaceae first described as a genus in 1775. It is native to South America and Central America.
Rhigospira is a genus of flowering plants in the family Apocynaceae, first described as a genus in 1878 by John Miers. The species, Rhigospira quadrangularis was first described as Ambelania quadrangularis by Johannes Müller Argoviensis in 1860 but was transferred to the genus, Rhigospira, in 1878 by John Miers. The genus contains only one known species, Rhigospira quadrangularis, native to northwestern South America.
Rapatea is a group of plants in the family Rapateaceae described as a genus in 1775.
Hevea guianensis is a species of rubber tree in the genus Hevea, belonging to the family Euphorbiaceae. It is native to the rainforests of Ecuador, Venezuela, the Guyanas, Brazil, Colombia and Peru. It generally grows on well-drained soils or on those that are only lightly inundated, on river banks, in gallery forests, savannah forests and wooded slopes.
Hevea benthamiana is a species of rubber tree in the genus Hevea, belonging to the family Euphorbiaceae. A medium-sized deciduous tree growing to a height of about 27 m (90 ft), it is native to the rainforests of northern Brazil, Colombia and Venezuela.
Hevea microphylla is a species of rubber tree in the genus Hevea, belonging to the family Euphorbiaceae. It is native to the Amazon basin where it occurs in Venezuela, Colombia and northern Brazil. It was first described in 1905 by the German botanist Ernst Heinrich Georg Ule. It is the only member of the genus to be included in the subgenus Microphyllae.
Tibouchina aspera is a species of flowering plant in the family Melastomataceae, native to Central America and tropical South America. It was first described by Jean Fusée Aublet in 1775. In the original description of the species, it was suggested that the plant was inhaled to treat chest pain and dry coughs.