Federal and State Listed Species of Texas:
Texas ayenia
Global Location
Texas ayenia grows in south Texas in Cameron, Hidalgo, and Willacy counties, as well as in northern Mexico in Coahuila, Durango, and Tamaulipas.
Description
Texas ayenia is a 1.5 m tall, thornless shrub with heart-shaped leaves that have saw-toothed edges. Older stems of Texas ayenia have rust-colored spots, which are variable in shape (round to linear). Arising from the stem at the same point as the 3.5-12.5 cm long by 2-7.5 cm wide leaves, the small, yellowish-green flowers hang in clusters of three (rarely four). Petals are U-shaped with the base of the U attached to the flower. The small round fruits are prickly and have five lobes, which break apart into five sections when the fruit dries.
Similar Species
Hairy ayenia (Ayenia pilosa) is much smaller (10-20 cm tall), has reddish, triangular petals, and two different leaf shapes (lower leaves are more round and upper leaves are more egg-shaped). Texas ayenia can be distinguished from other similar-appearing mallows by its prickly, 5-sectioned fruit, and the reddish-brown spots on its older stems. If flowers are present, these species can easily be differentiated from one another.
Floral Characters
nullLeaf Characters
nullHabitat
This plant can be found on well-drained soils in subtropical thorny woodlands and tall shrublands of the Rio Grande delta.
Life Cycle Events
Flowering can occur throughout the year with adequate rainfall.
Survey Season
As a woody perennial, Texas ayenia can be recognized year-round, although identification may be easier when flowers and or fruits are present.
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Additional Information
- Rare Plants of Texas
- U.S. Fish and Wildlife Service
- NatureServe
- Flora of North America
- Center for Plant Conservation
- Pronatura Noreste, A.C. 2005. Status, distribution, and conservation of three species of rare plants in the Lower Rio Grande in Mexico. Section 6 final report. Austin: Texas Parks & Wildlife Department.
Comments
In 1994, when Texas ayenia was listed as endangered, there was one known site in South Texas. However, 25 new sites have been found in both the Rio Grande Valley and in northern Mexico. Although newly located populations of Texas ayenia have increased the plant’s chance of recovery, habitat loss and encroachment of invasive grasses are severe enough that this species continues to be listed as endangered.