Monographs Details: Lotus strigosus var. tomentellus (Greene) Isely
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.
Description:Distribution and Ecology - Range as given in key; desert slopes and washes, usually with creosote bush; rocky desert mt. foothills, canyons; abundant and conspicuous along roadsides in favorable springs. Ca. 0-4500(-7400) ft. Feb.-May.
Discussion:L. tomentellus Greene (1890); Hosackia tomentella (Greene) Abrams (1944); L. strigosus var tomentellus (Greene) Isely (1978).
Lotus strigosus var tomentellus, the eastern desert form of the complex, in Arizona is easily recognized by its short peduncles and commonly cinereous pubescence. The plants average smaller than those of var strigosus. The leaflets are mostly of the broader, 2-3 r, type, and the commonly short 1-2 cm, pods are proportionately broader than of the California relatives. The small, 5-8 mm, flowers, usually with a narrower keel, frequently do not open, and presumably are cleistogamous. Arizona botanists have reasonably regarded L. tomentellus as different from L. strigosus of California, a view that, however, is rendered untenable by intermediates in southern California.
A few Arizona plants that have long peduncles, but which are not contiguous to the immediate genetic influence of Lotus strigosus vars hirtellus and strigosus, are classified as phases of var tomentellus.
Var tomentellus phase 1
Pubescence incurved, sometimes scant, and leaves greenish; peduncles commonly exceeding 1.5 cm; flowers small, rarely exceeding 8 mm, seeds both cuboid-rugose and spheroid-smooth. Interior s California, slightly into Arizona.
These, the most common intermediates between Lotus strigosus vars strigosus and tomentellus (possibly also var hirtellus) have usually been identified as L. tomentellus because they have the pubescence of that species. But peduncle length is more characteristic of var strigosus, and seed types are various. These intermediates are more common than suggested by Map 57 because I have associated most atypical specimens with the variety they more closely resemble. Only exact intermediates are mapped separately. The reverse character combination, in which the foliage and pubescence of var strigosus coincides with the short peduncles of var tomentellus, much less frequent, is phase 2 of var strigosus.
Var tomentellus phase 2 Not mapped
As Lotus strigosus var tomentellus, but either with pubescence of var strigosus, or peduncles to 15 mm, or both. Arizona.
These represent a few specimens from Lotus strigosus var tomentellus domain that resemble var strigosus. Perhaps var tomentellus carries some var strigosus characters that sporadically emerge in Arizona. Or possibly the unity of the varieties has been molested by the casual introduction of var strigosus in disturbed areas beyond its original range.