Species of Greatest Conservation Need

**Species of Greatest Conservation Need** (Updated: 06/16/2025)
Scientifc Name	Common Name	Taxonomic Group	SGCN Status	Federal Status	State Status	Global Rank	State Rank	Endemic	General Habitat Type(s)
Tradescantia pedicellata	granite spiderwort	Plants	Yes	Not Listed	Not Listed	G2Q	S2	Yes	Mostly in fractures on outcrops of granite, gneiss, and similar igneous and metamorphic rocks, or in early successional grasslands or forb-dominated assemblages on well-drained, sandy to gravelly soils dervied from same; flowering at least April-May
Tragia nigricans	darkstem noseburn	Plants	Yes	Not Listed	Not Listed	G3	S3	Yes	Occurs in oak-juniper woodlands on mesic limestone slopes and canyon bottoms; Perennial; Flowering/Fruiting April-Oct
Trichocoronis wrightii var. wrightii	Wright's trichocoronis	Plants	Yes	Not Listed	Not Listed	G4T3	S2	No	Most records from Texas are historical, perhaps indicating a decline as a result of alteration of wetland habitats; Annual; Flowering Feb-Oct; Fruiting Feb-Sept
Tridens buckleyanus	Buckley tridens	Plants	Yes	Not Listed	Not Listed	G3G4	S3S4	Yes	Occurs in juniper-oak woodlands on rocky limestone slopes; Perennial; Flowering/Fruiting April-Nov
Trillium texanum	Texas trillium	Plants	Yes	Not Listed	Not Listed	G3	S3	No	In or along the margins of hardwood forests on wet acid soils of bottoms and lower slopes, strongly associated with forested seeps and baygalls; flowering March-May
Triphora trianthophoros var. texensis	Texas three-birds orchid	Plants	Yes	Not Listed	Not Listed	G4?T1Q	S1	Yes	base of short, shallow, intermittent drainage slope with high organic matter (leaf-litter mulch) in dense, mixed hardwood (Southern red oak, hickory) pine (Shortleaf) forest stand; flowers from late July to early September
Valeriana texana	Guadalupe valerian	Plants	Yes	Not Listed	Not Listed	G2	S2	No	Pine-oak-juniper woodlands and moist crevices in limestone boulders and cliff faces in higher canyons of the Guadalupe Mountains; Perennial; Flowering April-Aug; Fruiting July
Valerianella florifera	Texas cornsalad	Plants	Yes	Not Listed	Not Listed	G3	S3	Yes	Grasslands and early-successional openings in the post oak belt of east-central and northeast Texas; Sandy soils; Annual; Flowering March-April
Valerianella stenocarpa	bigflower cornsalad	Plants	Yes	Not Listed	Not Listed	G3	S3	Yes	Usually along creekbeds or in vernally moist grassy open areas (Carr 2015).
Valerianella texana	Edwards Plateau cornsalad	Plants	Yes	Not Listed	Not Listed	G2	S2	Yes	Very shallow, well-drained, but seasonally moist gravelly-sandy soils derived from igneous or metamorphic rocks, often along the downslope margin of rock outcrops, in full sun or in partial shade of oak-juniper woodlands; more likely encountered in early successional areas; population numbers fluctuate considerably from year to year, with higher numbers following winters with higher rains and/or moderate temperatures; peak flowering/fruiting mid-March�late April, stems wither and disappear by the beginning of May
Viola guadalupensis	Guadalupe Mountains violet	Plants	Yes	Not Listed	Not Listed	G1	S1	Yes	Guadalupe Mountains; bullet hole openings in dolomitized limestone rock faces, in the shade of an open Douglas-fir (Pseudotsuga menziesii) woodland at about 2,450 m (8,000 ft) elevation; flowering March-May
Vitis rupestris	rock grape	Plants	Yes	Not Listed	Not Listed	G3	S1	No	Occurs on rocky limestone slopes and in streambeds; Perennial; Flowering March-May; Fruiting May-July
Willkommia texana var. texana	Texas willkommia	Plants	Yes	Not Listed	Not Listed	G3G4T3	S3	Yes	Mostly in sparsely vegetated shortgrass patches within taller prairies on alkaline or saline soils on the Coastal Plain (Carr 2015).
Wissadula parvifolia	small-leaved yellow velvet-leaf	Plants	Yes	Not Listed	Not Listed	G1	S1	Yes	Occurs on sandy loams or clays in shrublands or woodlands on gently undulating terrain of the Holocene sand sheet over the Goliad Formation.
Xanthisma viscidum	sticky tansy aster	Plants	Yes	Not Listed	Not Listed	G3	S2	No	Occurs on calcareous or sandy soils in Chihuahuan Desert shrublands or mesquite grasslands.
Xylorhiza wrightii	Wright's machaeranthera	Plants	Yes	Not Listed	Not Listed	G3	S3	No	Desert grasslands in the Trans-Pecos (Carr 2015).
Xyris chapmanii	Chapman's yellow-eyed grass	Plants	Yes	Not Listed	Not Listed	G3	S3	No	Mostly in soft, spongy, peaty substrates in deep muck seepage bogs; mostly in muckiest parts of hillside seepage bogs; flowering August-September, with seed maturing September-October
Xyris drummondii	Drummond's yellow-eyed grass	Plants	Yes	Not Listed	Not Listed	G3G4	S2	No	Wet sand or peaty sand in hillside seepage bogs; in Texas, exclusively over the Catahoula formation, elsewhere also found along contact between Willis and Bentley formations; flowering mid June-mid August, seeds developing mid-late summer and early fall
Xyris scabrifolia	roughleaf yellow-eyed grass	Plants	Yes	Not Listed	Not Listed	G3	S2	No	Wet sand and/or peat in acid seepage areas or hillside seepage bogs on the Catahoula formation or near the contact of the Catahoula and the Willis formations, in open areas and in partial shade of evergreen shrub thickets, often on Sphagnum hummocks; flowering late July-early September
Yucca cernua	nodding yucca	Plants	Yes	Not Listed	Not Listed	G2	S1	Yes	Openings in and margins of pine-hardwood forests on brownish acid clays of the Redco Series; flowering/fruiting June-November
Yucca necopina	Glen Rose yucca	Plants	Yes	Not Listed	Not Listed	G3	S3	Yes	Grasslands on sandy soils and limestone outcrops; flowering April-June
Zanthoxylum parvum	Shinners' tickle-tongue	Plants	Yes	Not Listed	Not Listed	G2	S2	Yes	Understory of maple-oak woodlands or evergreen oak shinnery on rocky, often shallow, well-drained, neutral, non-calcareous loams underlain by rhyolite, tuff trachyandesite, or other igneous rock, at elevations between about 1,350-1,750 m (4,400-5,750 ft); flowering late March-early April, before the leaves have fully expanded
Zephyranthes jonesii	Jones's rainlilly	Plants	Yes	Not Listed	Not Listed	G3	S3	Yes	Hardpan swales and other seasonally moist low areas (Jones 1977). Flowering mid summer--early fall (Jul--Oct) (Flagg, Smith & Flory 2002).
Zephyranthes refugiensis	Refugio rainlily	Plants	Yes	Not Listed	Not Listed	G2G3	S2S3	Yes	Occurs on deep heavy black clay soils or sandy loams in swales or drainages on herbaceous grasslands or shrublands on level to rolling landscapes underlain by the Lissie Formation.
Zephyranthes smallii	Small's rainlily	Plants	Yes	Not Listed	Not Listed	G1Q	S1	Yes	Open low fields, swales and ditches on sandy loam. Flowering early fall (Sep--Oct) (Flagg, Smith & Flory 2002).