Texas Ayenia (Ayenia limitaris)

Photograph of the Texas Ayenia


Other Names
Tamaulipan Kidneypetal, Rio Grande Ayenia
Texas Status
U.S. Status
Endangered, Listed 8/24/1994
Texas ayenia is a thornless medium-sized shrub, two to five feet tall. The leaves are 1 1/2-3 inches long, simple, alternate, and hairy. They have toothed margins and are shaped like an inverted teardrop. The flowers are small and clustered in the upper leaves, with five green, pink, or cream colored petals. The fruit is a round, five-celled capsule about 1/4 inches in diameter and covered with short, curvy, sharp prickles.
Life History
Little is know about the reproductive biology of this species, a member of the chocolate family. Texas ayenia may be dependent on flooding for nutrient deposition and seed dispersal. Propagation techniques are being developed by the U.S. Fish and Wildlife Service at the Lower Rio Grande Valley National Wildlife Refuge. Plants growing in association with Texas ayenia include coma, brasil, mesquite, lotebush, granjeno, colima, and snake-eyes. This plant community was once an extensive thicket that covered most of the Rio Grande delta; however, less than 5% of the original acreage remains, mainly along fence rows, highway right-of-ways, canals, and ditch banks.

Habitat loss is thought to be the major threat to the continued existence of this species. Much of the native brush within the historical range of Texas Ayenia has been converted to agricultural or urban use. Flood control may be of particular importance to this species and the ecosystem upon which it depends. Introduction and spread of non-native species such as guinea grass (Panicum maximum) also poses a serious threat to the species. The small size of the existing U. S. population makes this species very vulnerable.
This species is found on terraces and floodplains. It grows in dense, relatively moist, subtropical riparian woodlands, with an overall canopy cover of about 95%.
Texas ayenia once occurred in Cameron and Hidalgo counties in south Texas, and in the states of Coahuila and Tamaulipas in Mexico. Today, Texas ayenia exists in the United States in only one small population of about 20 individuals in Hidalgo county.
Texas ayenia was listed as endangered by the U.S. Fish and Wildlife Service in August 1994. Landowners and managers can help by protecting remaining acreages of native subtropical woodland communities. Over 95% of this habitat has been lost to development in Texas, and each remaining acre is important in preserving examples of the native plant and animal diversity that once existed throughout the lower Rio Grande Valley.

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