1b. Tidestromia suffruticosa (Torrey) Standley var. oblongifolia (S. Watson) Sánchez del Pino & Flores Olvera, Novon. 12: 406. 2002.
Cladothrix oblongifolia S. Watson, Proc. Amer. Acad. Arts 17: 376. 1882; C. cryptantha S. Watson; Tidestromia oblongifolia (S. Watson) Standley; T. oblongifolia subsp. cryptantha (S. Watson) Wiggins
Leaf blades usually oblong (ovate-oblong, circular, lanceolate, or ovate). Internodes of secondary branches subtending involucres in fruit usually reduced and crowded.
Flowering year-round. Desert shrub, mesquite dunes, creosote bush scrub, crevices of lava rocks, roadsides, in sandy, clayey, gravelly, limestone, travertine, alluvial, and saline soils, basaltic rocky loam; 0-1300 m; Ariz., Calif., Nev., Tex., Utah; Mexico (Baja California, Sonora).
F. Shreve and I. L. Wiggins (1964) recognized two subspecies of Tidestromia oblongifolia: subsp. oblongifolia characterized by oblong leaf blades 2-15 mm wide and involucres ca. 1 mm, and subsp. cryptantha, with orbiculate leaf blades 2-7 mm wide and involucres ca. 3-4 mm. These characters show a wide range of variation; the described taxa do not appear to be distinct subspecies.