Jasminocereus

''Jasminocereus'' (meaning "jasmine-like cereus", referring to the flowers) is a genus of cacti with only one species, ''Jasminocereus thouarsii'', endemic to the Galápagos Islands, territorially a part of Ecuador. In English it is often called the candelabra cactus (a name used for other cacti with a similar appearance). At maturity it has a branched, treelike habit, and may be up to tall. The stems are made up of individual sections with constrictions between them. Its creamy white to greenish flowers open at night and are followed by greenish to reddish fruits.

Description

''Jasminocereus thouarsiii'' is a leafless treelike cactus growing to tall, with green or greenish yellow branching stems made up of individual sections long. The trunk and branches have 11–22 ribs. The areoles have up to 35 spines, each up to long. The spines vary in colour from white through to black, darkening with age. The flowers, borne singly, open at night, and are up to across, with many creamy white to yellow or olive green petals and numerous stamens. The fruit is a berry, greenish to reddish purple in colour, containing many black seeds. Three varieties are recognized by some sources; they are said to vary in height, flower texture and fruit colour, among other features.

Varieties

Three varieties are sometimes recognized:
*''Jasminocereus thouarsii'' var. ''thouarsii'' has flowers that are not waxy and green fruits. It is usually under tall. It occurs on the islands of Floreana, Isabela, San Cristóbal and Santa Cruz.
*''Jasminocereus thouarsii'' var. ''delicatus'' ( E.Y.Dawson) E.F.Anderson & Walk. has flowers that are not waxy and reddish purple fruits. It is found on Santa Cruz and Santiago, and is said to be the species most likely to be seen by visitors to the Galápagos.
*''Jasminocereus thouarsii'' var. ''sclerocarpus'' (Schum.) E.F.Anderson & Walk. has waxy flowers and green fruits, and the largest number of spines per areole. It occurs only on Fernandina and Isabela.

Following David Hunt et al. in 2006, the IUCN Red List does not recognize any varieties.

A branchy cactus on the galapagos islands.jpg, Growth habit
Jasminocereus thouarsii var. thouarsii (6208013877).jpg, Stems
Jasminocereus thouarsii (6208528580).jpg, Flower
Jasminocereus thouarsii fruit.jpg, Fruit

Taxonomy

The nomenclature of the genus and species is somewhat tangled. In 1899, Frédéric Weber described two species, ''Cereus thouarsii'' and ''Cereus galapagensis''. His descriptions are brief and refer in part to information received from others; he also notes that neither the flowers nor the fruit of ''Cereus galapagensis'' were known. The specific epithet ''thouarsii'' refers to Abel Aubert du Petit-Thouars, who found both species some 30 years earlier when his ship visited the Galápagos. In 1920, Nathaniel Lord Britton and Joseph Nelson Rose erected the genus ''Brachycereus'', synonymizing both Weber's ''Cereus thouarsii'' and another cactus from the Galápagos, ''Cereus nesioticus'', under the name ''Brachycereus thouarsii''. They placed Weber's ''Cereus galapagensis'' in a separate new genus, ''Jasminocereus'', as ''Jasminocereus galapagensis''. In 1935, Curt Backeberg realized that only ''Cereus nesioticus'' was the ''Brachycereus'' of Britton and Rose, and later placed Weber's ''Cereus thouarsii'' in ''Jasminocereus''. In 1971, Anderson and Walkington carried out fieldwork and studied herbarium material, and decided that Weber's two species were actually the juvenile and mature forms of the same species. The earliest epithet for the species is ''thouarsii''.

Additional species of ''Jasminocereus'' have been described, but they are now regarded as part of a single species, which may be divided into three varieties. ''J. sclerocarpus'' is then a synonym of ''J. thouarsii'' var. ''sclerocarpus'' and ''J. howellii'' of ''J. thouarsii'' var. ''delicatus''. Other sources do not recognize distinct varieties.

Phylogeny and classification

Molecular studies show that the two endemic Galápagos genera, ''Jasminocereus'' and ''Brachycereus'', are sisters, with their closest relative being the South American mainland species ''Armatocereus'':

In one widely used classification of cacti, ''Armatocereus'' and ''Jasminocereus'' are placed in the tribe Browningieae of the subfamily Cactoideae, and ''Brachycereus'' is placed in the tribe Trichocereeae, which is inconsistent with the cladogram above. A classification produced in 2010 by Nyffeler and Eggli puts all three genera in a much larger tribe Phyllocacteae.

Distribution and habitat

''Jasminocereus thouarsii'' is endemic to the Galápagos, where it is found on Fernandina, Floreana, Isabela, San Cristóbal, Santa Cruz and Santiago, plus some islets, including Bartolomé. It is found in arid areas, from the coast up to about on the larger islands.

Conservation

''Jasminocereus thouarsii'' was rated as "vulnerable" in the IUCN Red List of 2002, but this was downgraded to "least concern" in 2013. As with all plants and animals of the Galápagos, collecting or disturbing ''J. thouarsii'' is strictly controlled by the Ecuadorian government; the complete range of the species lies within the Galápagos National Park and Natural World Heritage Site. Trade in the species is controlled under CITES Appendix II.

Uses

The fruits of ''Jasminocereus thouarsii'' (particularly var. ''delicatus'' for those who distinguish varieties) have been used to make a fruit juice described as "refreshing".

See also

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References

External links

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{{Taxonbar, from=Q2524974

Cactoideae
Cactoideae genera
Endemic flora of Galápagos
Cacti of South America