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)
Selenia jonesii	Jones' selenia	Plants	Yes	Not Listed	Not Listed	G3	S3	Yes	Wet clayey soils of stream margins, playa lakes, and roadsides, mostly in the western Edwards Plateau; Annual; Flowering Feb-April; Fruiting March-April
Senecio quaylei	Quayle's butterweed	Plants	Yes	Not Listed	Not Listed	G1	S1	Yes	Known only from the type location in Parker County, where it occured in a weedy roadside ditch; Annual; Flowering spring
Senna orcuttii	Orcutt's senna	Plants	Yes	Not Listed	Not Listed	G2	S2	No	Gravelly or rocky soil on limestone slopes and in beds of intermittent streams, within various mid- to lower elevation Chihuahuan Desert communities; at least one site is on east- to north-facing slopes; flowering July-August
Senna ripleyana	Ripley's senna	Plants	Yes	Not Listed	Not Listed	G1	SH	No	Gravelly hilltops in arid grasslands and creosote flats in Chihuahuan Desert; elevation ranges 1,200-1,500 m (3,900-4,900 ft); flowering/fruiting July-October
Sesuvium trianthemoides	roughseed sea-purslane	Plants	Yes	Not Listed	Not Listed	GH	SH	Yes	Dunes and perhaps in saline clay of tidal flats or ephemeral ponds within a dune landscape; likely flowering June-August
Seymeria texana	Texas seymeria	Plants	Yes	Not Listed	Not Listed	G3	S3	Yes	Found primarily in grassy openings in juniper-oak woodlands on dry rocky slopes but sometimes on rock outcrops in shaded canyons; Annual; Flowering May-Nov; Fruiting July-Nov
Shinnersia rivularis	springrun whitehead	Plants	Yes	Not Listed	Not Listed	G2G3	S1	No	In shallow, slow-moving water in small, usually spring-fed streams and rivers arising from calcareous outcrops; abandoned river channel fed by a strong perennial stream, rooted in fine-textured sediments, with stems entirely submerged and only the flowering branch tips appearing above water surface; in slowly flowing water up to 0.3-0.4 m deep but appeared to be absent from deeper water, shaded for most of the day; also in water 0.5-1 m deep, rooted in a mucky to gravelly bottom; flowering throughout the year, most reliably March-May
Sicyos glaber	smooth bur-cucumber	Plants	Yes	Not Listed	Not Listed	G3	S1	No	Mesic canyons in the Chisos and Guadalupe Mountains (Carr 2015).
Silene plankii	Plank's catchfly	Plants	Yes	Not Listed	Not Listed	G2	S1	No	Franklin Mountains of El Paso County, occurring in crevices on shaded igneous cliff faces above ca. 5000 ft.; Perennial; Flowering summer-early autumn
Silene subciliata	scarlet catchfly	Plants	Yes	Not Listed	Not Listed	G3	S3	No	Deep well-drained sandy soils in and along margins of fire-maintained, dry, upland, longleaf pine savannas; in fire-suppressed forests with dense understory, it is often limited to sunnier roadsides or cleared utility easements; also sparingly in moister sands on openly forested creek banks; flowering early July-October, sometimes early November
Solanum davisense	Davis Mountains horse-nettle	Plants	Yes	Not Listed	Not Listed	G3	S2	No	Mostly in medium to high elevations in the Chisos, Davis and Chinati mountains of Brewster, Jeff Davis and Presidio counties, but also at lower-elevation sites; sometimes weedy where it occurs; Annual; Flowering/Fruiting June-Oct
Spigelia texana	Texas pinkroot	Plants	Yes	Not Listed	Not Listed	G3	S3	Yes	Woodlands on loamy soils; Perennial; Flowering March-Nov; Fruiting April-Nov
Spiranthes brevilabris	Texas ladies'-tresses	Plants	Yes	Not Listed	Not Listed	G1G2	S1	No	Sandy soils in moist prairies, incl. blackland/Fleming prairies, calcareous prairie pockets surrounded by pines, pine-hardwood forest, open pinelands, wetland pine savannahs/flatwoods, and dry to moist fields, meadows, and roadsides. Delicate, nearly ephemeral orchid, producing winter rosettes, flowers Feb-Apr. Historically endemic to SE coastal plain.
Spiranthes longilabris	giant spiral ladies'-tresses	Plants	Yes	Not Listed	Not Listed	G3	S1	No	Restricted to wetland pine savannas; Low woods, wet open areas; Perennial; Flowering Oct-Dec; Fruiting Nov
Spiranthes parksii	Navasota ladies'-tresses	Plants	Yes	E 05/06/1982	E 04/29/1983	G3	S3	Yes	Openings in post oak woodlands in sandy loams along upland drainages or intermittent streams, often in areas with suitable hydrologic factors, such as a perched water table associated with the underlying claypan; flowering populations fluctuate widely from year to year, an individual plant does not flower every year; flowering late October-early November (-early December)
Stanleya pinnata var. texana	Texas golden prince's-plume	Plants	Yes	Not Listed	Not Listed	G5T1	S1	Yes	Occurs on clay or silty soils on sparsely vegetated limestone and/or gypseous hills, draws, washes, and flats.
Stenaria butterwickiae	Mary's bluet	Plants	Yes	Not Listed	Not Listed	G1	S1	Yes	Shallow pockets or crevices in limestone bedrock on ridgetops; flowering or fruiting at least May-August
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.