Hymenoxys texana
(Coult. & Rose) Cockerell
Prairie Dawn
G2ImperiledGlobal Rank
HighThreat Impact
U.S. Fish & Wildlife Service, https://www.usa.gov/government-works
Identity
Unique IDELEMENT_GLOBAL.2.153540
Element CodePDAST530L0
Record TypeSPECIES
ClassificationSpecies
Classification StatusStandard
Name CategoryVascular Plant
Endemicendemic to a single state or province
KingdomPlantae
PhylumAnthophyta
ClassDicotyledoneae
OrderAsterales
FamilyAsteraceae
GenusHymenoxys
Synonyms
Actinella texanaJ.M. Coult. & Rose
Other Common Names
prairiedawn (EN) Texas prairie dawn-flower (EN)
Concept Reference
Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
Conservation Status
Rank MethodLegacy Rank calculation - Excel v3.1x
Review Date2016-07-18
Change Date1988-05-06
Edition Date2016-07-18
Edition AuthorsRoth, E., rev. Poole/Maybury (1996), rev. Treher (2016)
Threat ImpactHigh
Range Extent20,000-200,000 square km (about 8000-80,000 square miles)
Number of Occurrences6 - 80
Rank Reasons
Endemic to saline prairies with cryptogamic soils within the Houston Coastal Prairie. Although nearly 60 sites are known for this species, almost all are threatened by development from the expanding city of Houston. Many of the sites are within 1 km of each other and probably form a single population. Some sites have been destroyed within a year of their discovery due to development.
Range Extent Comments
Endemic to Fort Bend, Harris, and Trinity County.
Occurrences Comments
Reported from 61 sites but many of the sites are close enough to make 30 or less occurrences with a 1km separation distance. Reported from La Salle County in the 1800's but the specimen has not been located. There are similarities at the La Salle site with the other sites but no plants have been found there.
Threat Impact Comments
Habitat destruction for housing development on private land is the primary threat to the species. Many occurrences are on private land in a county that is under rapid development. The construction of a beltway highway is responsible for the extirpation of one site.
Ecology & Habitat
Habitat
Poorly drained, sparsely vegetated areas ("slick spots") at the bases of small mounds (mima or pimple mounds) in open grassland or in almost barren areas. Soils are slightly saline, sticky when wet and powdery when dry. Plant associated include Texas windmill-grass (Chloris texensis) and Houston machaeranthera (Machaeranthera aurea), Thurovia triflora, Valerianella florifera, Willkommia texana var. texana, and Atriplex texana (Singhurst 2014).
Terrestrial Habitats
Grassland/herbaceous
Other Nations (1)
United StatesN2
| Province | Rank | Native |
|---|---|---|
| Texas | S2 | Yes |
Threat Assessments
| Threat | Scope | Severity | Timing |
|---|---|---|---|
| 1 - Residential & commercial development | Large (31-70%) | Extreme - serious | High - moderate |
| 1.1 - Housing & urban areas | Pervasive (71-100%) | Extreme - serious | High - moderate |
Plant Characteristics
DurationANNUAL
Economic Value (Genus)No
Roadless Areas (1)
Texas (1)
| Area | Forest | Acres |
|---|---|---|
| Big Creek | National Forests in Texas | 1,447 |
References (4)
- Correll, D.S., and M.C. Johnston. 1970. Manual of the vascular plants of Texas. Texas Research Foundation, Renner. 1881 pp.
- Flora of North America Editorial Committee (FNA). 2006c. Flora of North America north of Mexico. Vol. 21. Magnoliophyta: Asteridae, part 8: Asteraceae, part 3. Oxford Univ. Press, New York. xxii + 616 pp.
- Kartesz, J.T. 1994. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. 2nd edition. 2 vols. Timber Press, Portland, OR.
- Singhurst, JR, N. Shackelford, W. Newman, J.N. Mink, and W.C. Holmes. 2014. The ecology and abundance of <i>Hymenoxys texana</i> (Asteraceae). Phytoneuron 2014-19:1–19.