Navasota Ladies'-tresses (Spiranthes parksii)
- Texas Status
- U.S. Status
- Endangered, Listed 5/06/1982
- There are 14 or 15 different ladies'-tresses in Texas, and during the fall one or another of these orchids can be seen in almost any habitat in the eastern half of the state. Finding ladies-tresses can be difficult, since these orchids are not as conspicuous as their tropical cousins. Most Texas species produce a single slender, twisted spike of tiny white flowers, and in many habitats the ladies-tresses spike is much shorter than surrounding
This member of the orchid family is an erect, slender-stemmed perennial herb, 8-15 inches tall. The roots are clusters of fleshy tubers. Leaves are long and thin and found primarily at ground level, but are usually gone by flowering time. Flowers are creamy white and arranged in a loose spiral up the stem. Conspicuously white-tipped bracts occur underneath each 1/4 inch-long flower. Flower petals are round or oval. The side petals have a green central stripe, and the lip (bottom petal) is distinctly ragged.
- Life History
- Navasota ladies'-tresses bud from early to late October, flower from mid-October to mid-November, and form fruit from mid-October to the first frost (usually late November). The fruit breaks apart during mid-November and December. Each fruit normally contains thousands of microscopic seeds which are not easily cultivated. After frost, the plants die back and do not reappear until early spring, when basal rosettes can be seen.
Populations of Navasota ladies'-tresses are known to fluctuate from year to year. It is thought that cool, wet conditions (without hard frosts) between January and May provide ideal growing conditions for this orchid. Like other orchids, Navasota ladies'-tresses are often found in areas that are slightly wetter than surrounding areas of the landscape, although surface moisture may not be obvious.
This species has a limited range and low population numbers. It has been impacted by habitat loss and degradation due to urban development (primarily in the Bryan/College Station area), road construction, lignite mining, and oil and gas development. Collection by hobbyists and unscrupulous commercial operators remains a threat, especially since orchids tend to attract wide and intense interest.
These orchids appear to be adapted to common rangeland management practices used in the post oak savannah region. Controlled fire, proper grazing, and selective brush management are not considered detrimental. When needed, herbicides should be used carefully. Individual plant treatments for brush species on rangeland are not a problem; however, broadcast herbicides should not be used during the growing season in habitat areas.
- Navasota ladies-tresses is endemic to the Oak Woodlands and Prairies region of east-central Texas. They occur primarily in seasonally moist soils along open wooded margins of creeks, drainages, and intermittent tributaries of the Brazos and Navasota Rivers. Navasota ladies'-tresses is thought to require small-scale, patchy natural disturbances that provide canopy openings necessary to maintain habitat.
- When Navasota ladies'-tresses was listed as endangered, only two populations were known, both in Brazos County. Once thought to be extremely rare, it is now known to be locally common in parts of its range. Since 1982, many more populations have been discovered in Brazos, Burleson, Fayette, Freestone, Grimes, Jasper, Leon, Madison, Milam, Robertson, and Washington Counties.
- Navasota ladies'-tresses was listed as endangered by the U.S. Fish and Wildlife Service (USFWS) in May 1982, and listed as endangered by the State of Texas soon afterwards. Landowners can help protect this rare and beautiful orchid by learning more about Navasota ladies'-tresses and its habitat requirements. If you think you may have this plant on your property and would like help in identifying it, contact your local Natural Resources Conservation Service office for assistance.