Biserrula is a small genus of annual herbaceous legumes in the family Fabaceae (order Fabales), native to the Mediterranean Basin and surrounding regions. The genus is closely allied to other papilionoid legumes but is distinguished by its characteristic flattened, saw-toothed seed pods — a trait reflected in the genus name.
The genus comprises two currently accepted species: Biserrula pelecinus L. and Biserrula epiglottis (L.) Coulot, Rabaute & J.-M.Tison. Biserrula pelecinus is by far the better known of the two and is the sole species with significant agronomic attention. It has been under domestication in Australia since the late twentieth century as a drought-tolerant, acid-soil-adapted forage legume for dryland pastures, where it is valued for its nitrogen-fixing ability and its tolerance of low-fertility soils.
The natural range of the genus spans Portugal (including the island groups of Madeira and the Selvagens), the Canary Islands, all countries of the Mediterranean Basin, the Arabian Peninsula, and extends into East Africa as far south as Tanzania, reflecting a characteristic Mediterranean-to-arid-margin distribution.
Etymology
The name Biserrula derives from the Latin bi- (double, two) and serrula (a small saw), referring to the distinctively double-toothed or saw-edged margins of the flattened seed pods characteristic of the genus.
Distribution
Biserrula is native to the western and central Mediterranean region, occurring in Portugal (including Madeira and the Selvagens Islands), the Canary Islands, and all Mediterranean countries, as well as the Arabian Peninsula and East Africa south to Tanzania. Biserrula pelecinus has been introduced to southern Australia, where it has been selectively bred for use in dryland pastures.
Taxonomy Notes
The genus Biserrula was formerly monotypic, containing only B. pelecinus. Molecular and morphological revisions have now recognised a second species, B. epiglottis (L.) Coulot, Rabaute & J.-M.Tison, previously treated within other genera. GBIF places the genus in Fabaceae (order Fabales) with one accepted descendant in its backbone taxonomy, reflecting that B. epiglottis may not yet be fully integrated into all taxonomic databases.
