Contributed by Bruce A. Sorrie, Derick B. Poindexter, and Keith A. Bradley
A genus of about 350-360 species, herbs and shrubs, almost cosmopolitan.
ID notes:Recognizable by the "tractor seat"-shaped protuberance (scutellum) on the upper calyx. To discern annulate vs. non-annulate species, the corolla must be dissected to determine if a sharply defined ring of hairs (annulus) exists inside the corolla tube at the base of the calyx. *Note: in key break 26b, corollas of S. alabamensis may reach 22 mm long; its calyces are both stipitate glandular and punctate glandular, thus differing from S. arenicola and S. mellichampii. In key break 26a, corollas of S. mellichampii may be as short as 21 mm; its calyces are punctate glandular only, unlike S. incana var. australis which has both punctate glands and stipitate glands on calyces.
Ref: Bradley (2020) In Weakley et al. (2020); Collins (1976); Epling (1942); Harley et al. In Kadereit (2004); Leonard (1927); Pittman (1988); Poindexter & Weakley (2018a) In Weakley et al. (2018a); Shinners (1964). Show full citations.