Federal and State Listed Species of Texas:
Texas prairie dawn
Texas prairie dawn is only known from the Texas Gulf Coastal Plain in Fort Bend, Gregg, Harris, and Trinity counties.
Texas prairie dawn is a delicate, 3.5-18 cm tall annual with a green to reddish, 4-7+ cm wide rosette of paddle-shaped leaves. These leaves persist on the plant past the blooming period. Although most of the leaves are at the plant’s base, a few smaller leaves grow from the thin sprawling floral stalks. Leaves are ≤4 cm long, have three conspicuous veins on their underside, and can be shallowly lobed, saw-toothed, or smooth-edged. Two rows of overlapping green, leaf-like structures closely cup the outside base of the flower head. The inner row usually has a purple dot on each structure. Flower heads are yellow with no obvious “petals” (actually tiny flowers called ray florets) because they are hidden behind the leaf-like structures. The flat-topped flower head is composed of a tight disc of 40-75+ very small, yellow flowers. Each of these is called a disc floret and is only 1.5-2.1 mm long. The fruits that develop from this disc are cylindrical to pyramidal and are 1.5-2 mm long.
A new species, pygmy prairie dawn (Hymenoxys perpygmaea), has recently been described from Lamar County (Mink et al. 2012). Pygmy prairie dawn is more erect, has smaller rosettes at 1.3-2.4 cm wide, has shorter-lived basal leaves (which wither before or during flowering), and has 17-32 disc florets.
Texas prairie dawn occurs at the base of small mounds in grasslands in poorly drained, sparsely vegetated areas. It is also found in almost barren areas on slightly salty soils.
Life Cycle Events
Flowering occurs from February to April. By summer the habitat dries out and the only traces of Texas prairie dawn are the seeds in the soil.
As an annual, Texas prairie dawn can mostly easily be found in the spring around February, March and April when the plant is in bloom. The plant can be identified from the basal rosette of leaves, which forms just prior to flowering and withers and dies after seed dispersal.
- Mink, J., J. Singhurst, and W. Holmes. 2012. A new species of Hymenoxys (Asteraceae, Helenieae, Tetraneuridinae) from Texas. Novon. 22: 56-59.
As is true for many rare plants, the main threat to Texas prairie dawn is habitat destruction. Texas prairie dawn populations are mostly located within Harris County, an area of rapid development. The former common name, Texas bitterweed, did not help the plant’s image. To alleviate the negative attitude towards the plant, in 1989 the U.S. Fish and Wildlife Service held a contest, and school children were asked to think up new common names for the plant. Hence the common name Texas prairie dawn.