Monographs Details: Lotus benthamii Greene x L. scoparius (Nutt.) Ottley
Authority: Isely, Duane. 1981. Leguminosae of the United States. III. Subfamily Papilionoideae: tribes Sophoreae, Podalyrieae, Loteae. Mem. New York Bot. Gard. 25 (3): 1-264.
Discussion:Plants primarily of coastal habitats, commonly associated with the presumed parental species and with combinations of their characters. Stems glabrate, prostrate or low-ascending, thick and stiff or flexuous. Umbels peduncled or calyx lobes curved, or both. Corolla yellow.
Botanists informally allege hybridization or introgression between Lotus benthamii and L. scoparius. I have not established a formal category because evidence is observational and speculative. Most material that has L. benthamii calyces or distinctly peduncled umbels is retained with that species. Prostrate, often wiry plants that otherwise have L. scoparius characters are regarded as sand ecotypes of that species.
If these species hybridize, why does one not also find “typical” scantily foliose L. scoparius with pink flowers or the calyx lobes of L. benthamii?