Star Cactus

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Star Cactus

Astrophytum asterias

StatusEndangered
ListedOctober 18, 1993
FamilyCactaceae (Cactus)
DescriptionSmall, spineless cactus, brownish or dull green and speckled with tiny white scales; flowers are yellow with orange centers.
HabitatSparse, open brushland.
ThreatsCollecting; habitat loss due to agricultural development.
RangeTexas

Description

The star cactus is a small, spineless cactus. It is disk-or dome-like in shape, 0.7-6 in (2-15 cm) across and up to 2.7 in (7 cm) tall. This species is brownish or dull green and speckled with tiny white scales. Eight triangular sections are a result of vertical grooves dividing the main body. Each section is marked with a central line of circular indentations filled with straw-colored to whitish wooly hairs. The flowers are yellow with orange centers. These flowers are up to 2 in (5 cm) in diameter. The fruits are green to grayish-red, about 0.5 in (1.25 cm) long, oval, and fleshy.

Habitat

The star cactus is associated with low elevations in grasslands and shrublands. The area in which this cactus is found (Rio Grande Plains and Tamaulipan thorn shrub) was originally a subtropical grassland. Due to extensive suppression of fire and overgrazing, much of the area is now invaded with thorny shrub and tree species. The star cactus is found in sparse, open brushland, most commonly associated with partial shade of other plants or rocks growing on gravelly saline clays of loams overlaying the Tertiary Cathoula and Frio formations.

Distribution

Historically, the star cactus occurred in Cameron, Hidalgo, and Starr counties in Texas, and the adjacent states of Nuevo Leon and Tamaulipas in Mexico.

The star cactus is presently known from one locality in Texas and one in Tamaulipas, Mexico. Only about 2,100 plants are known to exist in the wild. The Nuevo Leon site is believed extirpated due to collecting activities. The Tamaulipas site has been reduced to very few individuals.

Threats

Much of the native habitat of the star cactus has been converted to agriculture or improved pasture. In the areas where this plant presently occurs, pasture improvement is done through a process of shrub clearing and then planting buffelgrass, Cenchhrus ciliaris. Therefore a mosaic of buffelgrass pasture and shrub stands results. It is unlikely that the star cactus would be able to withstand this type of land management. In Mexico, much of the once suitable habitat has been converted to corn fields or orange groves.

This cactus has been a favorite collection among succulent dealers for many years. Despite the fact that this plant is easily propagated, wild specimens are found in the commercial market. In Texas, about 400 wild specimens were found at one nursery.

Conservation and Recovery

As the star cactus is easily grown from seed and has been for many years by the succulent trade, propagation techniques are currently under investigation. Plants have been grown from seed in a greenhouse environment. These plants seems to be consistently hardier and more disease resistant than plants taken from the wild.

Contacts

U.S. Fish and Wildlife Service
Division of Endangered Species
P. O. Box 1306
Albuquerque, New Mexico 87103
http://southwest.fws.gov/

Austin Ecological Services Field Office
Compass Bank Building
10711 Burnet Road, Suite 20
Austin, Texas 78758

Arlington Ecological Services Field Office
Suite 252, 711 Stadium Drive East
Arlington, Texas 76011

Houston Ecological Services Field Office
17629 El Camino Real, Ste 211
Houston, Texas 77058

References

U.S. Fish and Wildlife Service. 18 October 1993 "Endangered and Threatened Wildlife and Plants; Determination of Endangered Status for the Plant Astrophytum asterias (Star Cactus)." Federal Register 58(199): 53804-53807.

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