Monographs Details: Lotus oroboides (Kunth) Ottley x L. rigidus (Benth.) Greene
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:Ottley (1944) said of specimens from the Santa Catalina Mts., Arizona, “[they] have the erect habit of L. rigidus, associated with the more delicate aspect of L. oroboides. ” I have also speculatively identified a few collections from the Pinal and Santa Catalina Mts. as this combination (ARIZ). My notes in part say: Nelson & Nelson 183: “Plants with the diffuse habit of L. oroboides var nanus but with long nodes and long, mostly 1-flowered peduncles with the aspect of L. rigidus.” McManus & McLaughlin 186: “with palmate small leaves and a bulky caudex.” Lemmon & Lemmon 17: “Habit of small L. rigidus, possibly procumbent, with short-peduncled, pubescent, highly elastic pods.” This collection was identified by Ottley as L. rigidus x wrightii. Such differences in judgements indicate their assumptive nature.