Texas Bitterweed

Hymenoxys texana

Description

Texas bitterweed, Hymenoxys texana, is a low-growing, single-stemmed or branching annual that grows up to 3.9 in (10 cm) high. Narrow, oblong leaves grow mostly from the base; upper stem leaves are smaller and less ragged. The plant bears clusters of small, yellow disk flowers from late March through April.

Habitat

The only known population of Texas bitterweed is found in the northern part of the coastal prairie, in poorly drained depressions of the open grassland, called "swales." Here, the sparse prairie vegetation is mostly dwarfed, and wild carrot is the dominant species.

Distribution

In the late 1870s, the species was collected from a site between the Nueces and Frio Rivers in southwest Texas, but recent surveys did not locate this population. The plant is thought to be endemic to Harris and Fort Bend Counties, Texas.

Since 1980, two populations of Texas bitter-weed—both in Harris County—were bulldozed to make way for residential developments. Several small populations survive in the area and in northern Fort Bend County. There are no current population estimates, but the U.S. Fish and Wildlife Service (FWS) considers the number of plants to be very low.

Threats

Further loss of its habitat is the most serious threat to Texas bitterweed. Plant sites are at the expanding edge of suburban development, north and west of metropolitan Houston. Surviving populations are on private land considered prime sites for development. The FWS hopes to strike a voluntary conservation agreement with landowners until more permanent arrangements can be devised. The plant is included on the Texas list of endangered plants.

Conservation and Recovery

The Mercer Arboretum, a county plant and wildlife facility near Humble, has begun work on bitterweed propagation and hopes to cultivate a stock of plants to replenish wild populations and for use in reintroduction efforts. Nursery propagation, however, is hampered by the low number of remaining plants. The reduced gene pool limits the bitterweed's ability to tolerate stress or change.

Contact

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

References

Correll, D. S., and M. C. Johnston. 1970. Manual of the Vascular Plants of Texas. Texas Research Foundation, Renner, Texas.

Mahler, W. F. 1982. "Status Report on Hymenoxys texana." U.S. Fish and Wildlife Service, Albuquerque.

U.S. Fish and Wildlife Service. 1986. "Determination of Endangered Status for Hymenoxys texana. Federal Register 51(49):8861-8863.

U.S. Fish and Wildlife Service. 1987. "Endangered and Threatened Species of Texas and Oklahoma (with 1988 Addendum)." U.S. Fish and Wildlife Service, Albuquerque.