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)
Stenaria mullerae var. pooleana	Jackie's bluet	Plants	Yes	Not Listed	Not Listed	G1Q	S1	Yes	North- to east-facing vertical limestone cliff faces in mid-elevation canyons in mountains in the Chihuahuan Desert; flowering May, perhaps to September
Streptanthus bracteatus	bracted twistflower	Plants	Yes	T 05/11/2023	Not Listed	G1	S1	Yes	Shallow, well-drained gravelly clays and clay loams over limestone in oak juniper woodlands and associated openings, on steep to moderate slopes and in canyon bottoms; several known soils include Tarrant, Brackett, or Speck over Edwards, Glen Rose, and Walnut geologic formations; populations fluctuate widely from year to year, depending on winter rainfall; flowering mid April-late May, fruit matures and foliage withers by early summer
Streptanthus carinatus ssp. carinatus	lyreleaf twistflower	Plants	Yes	Not Listed	Not Listed	G4T3T4	S3	No	Occurs on igneous and limestone slopes and alluvial fans (Carr 2015).
Streptanthus cutleri	Cutler's twistflower	Plants	Yes	Not Listed	Not Listed	G2	S2	No	Open shrublands or grasslands on calcareous gravel of talus slopes, rocky hillsides, and gravelly streambeds, at moderate elevations in the Chihuahuan Desert; flowering mostly February-March, sometimes into May
Streptanthus maculatus ssp. maculatus	clasping twistflower	Plants	Yes	Not Listed	Not Listed	G3T2T3Q	S2	No	Primarily on seasonally moist barrens on the Weches Formation but has been found elsewhere as well (Carr 2015)
Streptanthus platycarpus	broadpod twistflower	Plants	Yes	Not Listed	Not Listed	G3	S3	No	Western Edwards Plateau and the Trans-Pecos, seemingly disjunct in Llano Uplift area, occurring sparingly in various habitats; Biennial Annual; Flowering/Fruiting March-June
Streptanthus sparsiflorus	sparsely-flowered jewelflower	Plants	Yes	Not Listed	Not Listed	G2Q	S1	No	Shaded areas in gravelly limestone canyons and arroyos, often in dry creek beds at elevations ranging 1,200-1,800 m (3,900-5,900 ft); flowering May-June; populations vary widely in size from year to year depending on rainfall
Styrax platanifolius ssp. platanifolius	sycamore-leaf snowbell	Plants	Yes	Not Listed	Not Listed	G3T3	S3	Yes	Rare throughout range, usually in oak-juniper woodlands on steep rocky banks and ledges along intermittent or perennial streams, rarely far from some reliable source of moisture; Perennial; Flowering April-May; Fruiting May-Aug.
Styrax platanifolius ssp. stellatus	hairy sycamore-leaf snowbell	Plants	Yes	Not Listed	Not Listed	G3T3	S3	Yes	Rare throughout range, in habitats similar to those of var. platanifolius - usually in oak-juniper woodlands on steep rocky banks and ledges along intermittent or perennial streams, rarely far from some reliable source of moisture; Perennial; Flowering April-Oct; Fruiting May-Sept
Styrax platanifolius ssp. texanus	Texas snowbells	Plants	Yes	E 10/12/1984	E 01/09/1987	G3T1	S1	Yes	Limestone bluffs, boulder slopes, cliff faces, and gravelly streambeds, usually along perennial streams or intermittent drainages in canyon bottoms, in full sun or in partial shade of cliffs and/or Sycamore-Little walnut woodlands, oak-juniper woodlands, or mixed oak shrublands; flowering late March-April
Styrax platanifolius ssp. youngiae	Young's snowbell	Plants	Yes	Not Listed	Not Listed	G3T1	S1	No	In Mexico occurs in relatively mesic montane limestone canyons; known in Texas from a single specimen ��in a canyon, Davis Mountains�; flowering Apr-May, fruiting July-September
Symphyotrichum puniceum var. scabricaule	rough-stem aster	Plants	Yes	Not Listed	Not Listed	G5T2	S1S2	No	Relatively open sites in saturated soils associated with seepage areas, bogs, marshes, ponds, drainages, and degraded wetland remnants on the Queen City, Carrizo, and Sparta sand formations; flowering late September-early November.
Tauschia texana	Texas tauschia	Plants	Yes	Not Listed	Not Listed	G3	S3	Yes	Occurs in loamy soils in deciduous forests or woodlands on river and stream terraces; Perennial; Flowering/Fruiting Feb-April
Tetraneuris turneri	Billie's bitterweed	Plants	Yes	Not Listed	Not Listed	G3	S3	No	Grasslands on shallow sandy soils and caliche outcrops (Carr 2015).
Thalictrum arkansanum	Arkansas meadow-rue	Plants	Yes	Not Listed	Not Listed	G2Q	S2	No	Mostly deciduous forests on alluvial terraces and upper drainages of hardwood slope forests at contacts with calcareous prairies; flowering March-April, withering by midsummer
Thalictrum texanum	Texas meadow-rue	Plants	Yes	Not Listed	Not Listed	G2Q	S2	Yes	Mostly found in woodlands and woodland margins on soils with a surface layer of sandy loam, but it also occurs on prairie pimple mounds; both on uplands and creek terraces, but perhaps most common on claypan savannas; soils are very moist during its active growing season; flowering/fruiting (January-)February-May, withering by midsummer, foliage reappears in late fall(November) and may persist through the winter
Thelesperma burridgeanum	Burridge greenthread	Plants	Yes	Not Listed	Not Listed	G3	S3	Yes	Sandy open areas; Annual; Flowering March-Nov; Fruiting March-June
Thelocactus bicolor var. flavidispinus	straw-spine glory-of-Texas	Plants	Yes	Not Listed	Not Listed	G4T2	S2	Yes	Rocky hills of the Caballos Novaculite formation; in desert grasslands or shrublands below about 1,500 m (5000 ft); flowering late March-May, also June-September after significant rainfall
Thelypodiopsis shinnersii	Shinner's rocket	Plants	Yes	Not Listed	Not Listed	G2G3	S2	No	Mostly along margins of Tamaulipan thornscrub on clay soils of the Rio Grande Delta, including lomas near the mouth of the river; Tamaulipas, Mexico specimens are from mountains, with no further detail; flowering mostly March-April, with one collection in December
Thelypodium texanum	Texas thelypody	Plants	Yes	Not Listed	Not Listed	G3	S3	Yes	Locally frequent on gravelly slopes and in arroyo bottoms; Annual; Flowering/Fruiting Feb-April
Thurovia triflora	threeflower broomweed	Plants	Yes	Not Listed	Not Listed	G2G3	S2S3	Yes	Near coast in sparse, low vegetation on a veneer of light colored silt or fine sand over saline clay along drier upper margins of ecotone between between salty prairies and tidal flats; further inland associated with vegetated slick spots on prairie mima mounds; flowering September-November
Thymophylla tephroleuca	ashy dogweed	Plants	Yes	E 07/19/1984	E 01/09/1987	G2	S2	Yes	Grasslands with scattered shrubs; most sites on sands or sandy loams on level or very gently rolling topography over Eocene strata of the Laredo Formation; flowering March-May depending to some extent on rainfall
Tidestromia carnosa	fleshy tidestromia	Plants	Yes	Not Listed	Not Listed	G3	S2	No	Occurs in saline or gypseous soils in open situations; Annual; Flowering March-Nov; Fruiting April-Nov
Tillandsia baileyi	Bailey's ballmoss	Plants	Yes	Not Listed	Not Listed	G2G3	S2	No	Epiphytic on various trees and tall shrubs, perhaps most common in mottes of Live oak on vegtated dunes and flats in coastal portions of the South Texas Sand Sheet, but also on evergreen sub-tropical woodlands along resacas in the Lower Rio Grande Valley; flowering (February-)April-May, but conspicuous throughout the year
Tradescantia buckleyi	Buckley's spiderwort	Plants	Yes	Not Listed	Not Listed	G3	S3	No	Occurs on sandy loam or clay soils in grasslands or shrublands underlain by the Beaumount Formation.