Federal and State Listed Species of Texas:
Slender rushpea
Global Location
Slender rushpea is only known from the Texas Coastal Bend in Kleberg and Nueces counties.
Description
Slender rushpea is a perennial plant (8-20 cm tall) with horizontal stems that fan out from a woody taproot. Each winter the spineless, non-sticky stems die back and the taproot goes dormant. Leaf arrangement is intricate and compact. Arising from a longer, main stalk are two to three pairs of short stems opposite one another and a single short stem at the tip. Five to seven pairs of leaflets sprout from these shorter stems, and are also opposite one another. The underside of the tiny (2-5.5 mm long), oval leaflets are coated with a sparse layer of hair. Five green, leaf-like structures cup the base of the five egg-shaped petals, which range in color from yellow-pink, reddish-orange, to rose. These green, leaf-like structures are covered with a microscopic, but thick layer of hair. The straight, bean-like fruit pods contain 2-4 green-black seeds.
Similar Species
Slender rushpea is one of the many plants in the legume family, as revealed by the bean-like fruit and intricate leaf arrangement. Several other legumes resemble slender rushpea in Texas. Dwarf nicker (Hoffmannseggia drummondii) is a small shrub-like plant, which stands slightly taller (15-30 cm) than slender rushpea, and has crescent-moon shaped fruit pods. Hairs on the younger stems of dwarf nicker are greenish-yellow and capped with a brownish-red bead. Indian rushpea (Hoffmannseggia glauca) is an erect plant with yellow flowers and numerous sticky, red hairs. Netleaf bundleflower (Desmanthus reticulatus) and virgate bundleflower (Desmanthus virgatus) have tiny white linear flowers clustered closely, like a dandelion puffball. And finally, tornillo (Prosopis reptans) has a similar leaf arrangement to slender rushpea, but the stems have paired spines.
Floral Characters
nullLeaf Characters
nullHabitat
Slender rushpea occurs in openings amongst mesquite and other woody plants that have invaded short-grass coastal prairie remnants.
Life Cycle Events
Flowering occurs from April to November. Flowers are only open mid-day for a few hours.
Survey Season
Slender rushpea is most visible when in bloom April through November.
Citations
- Pressly, L. 2002. The effects of an invasive exotic grass species, Kleberg bluestem Dichanthium annulatum (Forsk.) Staph on the endangered slender rush-pea Hoffmannseggia tenella Tharp and Williams. Section 6 Final Report. Austin: Texas Parks & Wildlife Dept..
Additional Information
- Rare Plants of Texas
- U.S. Fish and Wildlife Service
- NatureServe
- Correll, D.S. and M.C. Johnston. 1970. Manual of the vascular plants of Texas. Texas Research Foundation. Renner, TX.
- Poole, J.M. and G.K. Janssen. 1997. Managing and monitoring rare and endangered plants on highway right-of-ways in Texas. Section 6 final report. Austin: Texas Parks & Wildlife Department.
Comments
As with many species that reside in South Texas, slender rushpea is negatively affected by competition with one or more non-native, invasive grass species. One study has shown that germination and establishment of slender rushpea decreases by 92% when Kleberg bluestem (Dicanthium annulatum) is planted with slender rushpea (Pressly 2002). This reduction may be due to Kleberg bluestem’s ability to more efficiently use nutrients and water compared to slender rushpea.