Annual or perennial herb; stems prostrate, often diffusely stems decumbent at base, 0,6-1(-2) m tall.
Ecology :
Sandy and gravelly soils; 0-500(-1600) m alt. (subsp. arabica); greens on volcanic lava rocks; ± 1700-2000 m alt. (subsp.tibestica Quézel) From N Africa to S Iran. The most variable species of the genus.
Bibliography17
Bull. Soc. Bot. France 46: 265-272. (1899). (1900).