Fimbristylis thermalis

S. Watson

Botany (Fortieth Parallel), 360. 1871.

Treatment appears in FNA Volume 23. Treatment on page 124. Mentioned on page 121, 123.

Plants perennial, robust, 50–150 cm, cespitose or with culms solitary; rhizomes scaly, slender, elongate. Leaves nearly distichous, spreading to ascending, 1/2 length of culms; sheath margins entire, backs smooth to pubescent; ligule present, complete; blades narrowly linear, proximally flat, 2–3.5(–4) mm wide, margins scabrid-ciliate, abaxial surface sometimes pubescent. Inflorescences: anthelae simple or compound, longer than wide; scapes wandlike, nearly terete or slightly compressed, distally 1 mm thick, marginal ribs scabrid; longest primary involucral bract shorter than panicle. Spikelets pale dull brown, lance-ovoid to cylindric-ellipsoid, 10–12 mm; fertile scales ovate, 3.5–4 mm, apex broadly acute, ciliate, surface uniformly puberulent, midrib excurrent as mucro or cusp. Flowers: stamens 3; styles 2-fid, flat, fimbriate. Achenes dark brown, lenticular-obovoid, 1.5 mm, finely cancellate, with 20 or more longitudinal rows of horizontally rectangular pits per side. 2n = 20.

Phenology: Fruiting spring–fall.
Habitat: Mineralized sands of hot springs, alkaline seep meadows
Elevation: 300–600 m


V23 188-distribution-map.jpg

Ariz., Calif., Nev., Utah, Mexico (Baja California, Coahuila).


Selected References


Lower Taxa