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Descript
Aloe vera is a stemless or very short-stemmed succulent plant growing to
60–100 cm (24–39 in) tall, spreading by offsets. The leaves are thick
and fleshy, green to grey-green, with some varieties showing white flecks on
the upper and lower stem surfaces. The margin of the leaf is serrated and has
small white teeth. The flowers are produced in summer on a spike up to
90 cm (35 in) tall, each flower being pendulous, with a yellow
tubular corolla 2–3 cm (0.8–1.2 in) long.Like other Aloe species,
Aloe vera forms arbuscular mycorrhiza, a symbiosis that allows the plant better
access to mineral nutrients in soil
Taxonomy and etymology
The species has a number of synonyms
A. barbadensis Mill., Aloe indica Royle, Aloe
perfoliata L. var. vera and A. vulgaris Lam.Common names
include Chinese Aloe, Indian Aloe, True Aloe, Barbados Aloe, Burn Aloe, First
Aid Plant.The species epithet vera means "true" or
"genuine". Some literature identifies the white spotted form of Aloe
vera as Aloe vera var. chinensis; however, the species varies
widely with regard to leaf spots and it has been suggested that the spotted
form of Aloe vera may be conspecific with A. massawana. The
species was first described by Carl Linnaeus in 1753 as Aloe perfoliata
var. vera, and was described again in 1768 by Nicolaas Laurens Burman as
Aloe vera in Flora Indica on 6 April and by Philip Miller as Aloe
barbadensis some ten days after Burman in the Gardener's Dictionary.
Techniques based on DNA comparison suggest that Aloe vera is
relatively closely related to Aloe perryi, a species that is endemic to
Yemen. Similar techniques, using chloroplast DNA sequence comparison and ISSR
profiling have also suggested that Aloe vera is closely related to Aloe
forbesii, Aloe inermis, Aloe scobinifolia, Aloe sinkatana,
and Aloe striata With the exception of the South African species A.
striata, these Aloe species are native to Socotra(Yemen), Somalia,
and Sudan. The lack of obvious natural populations of the species have led some
authors to suggest that Aloe vera may be of hybrid origin
Distribution
The natural range of Aloe vera is unclear, as the species has been widely
cultivated throughout the world. Naturalised stands of the species occur in the
southern half of the Arabian peninsula, through North Africa (Morocco,
Mauritania, Egypt) as well as Sudan and neighbouring countries, along with the
Canary, Cape Verde, and Madeira Islands. This distribution is somewhat similar
to the one of Euphorbia balsamifera, Pistacia atlantica, and a few others,
suggesting that a dry sclerophyl forest once covered large areas, but has been
dramatically reduced due to desertification in the Sahara, leaving these few
patches isolated. Several closely related (or sometimes identical) species can
be found on the two extreme sides of the Sahara: Dragon trees (Dracaena) and
Aeoniumbeing two of the most representative examples.
The species was introduced to China and various parts of southern Europe in
the 17th century. The species is widely naturalised elsewhere, occurring in
temperate and tropical regions of Australia, Barbados, Belize, Nigeria,
Paraguay and the United States It has been suggested that the actual species'
distribution is the result of human cultivation
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