Lotus strigosus (Nutt.) Greene
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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.
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Family
Fabaceae
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Scientific Name
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Description
Species Description - Basally branched, prostrate and mat-forming (-ascending and bushy-branched), usually diminutive or small (-robust), commonly subsucculent, annual .3-5 dm. Pubescence evident or inconspicuous, appressed, incurved, or hirsute. Leaves subsessile; leafstalk .3-2 cm, conspicuously flattened; leaflets subpetioluled, 49, paired or usually irregularly arranged, unequal (2-)3-10 mm, cuneate-obovate, elliptic, narrowly oblong or oblanceolate, acute or obtuse, (1.5-)2.5-5 r; cotyledons and tiny, trifoliolate seedling leaves sometimes persistent at anthesis. Stipules black dots. Peduncles in flower 3-25 mm, the longer ± or > leaves, further elongating in fruit or not, usually distally bracteate, with 1 -2(-3) flowers, (5-)6-10(-12) mm. Calyx tube 2-3.5 mm, teeth 1-2 mm. Corolla yellow, aging orange or red; standard ascending or remaining closely implicate, sometimes panduri-form, wings sometimes constricted on one or both sides, auriculate; keel with an obtuse or almost acute tip, auriculate or lacking an auricle. Stamens in two series. Ovary with 6-10 ovules; style defined by color and transverse line; stigma pen-icillate. Legume erect or divergent, straight to usually falcate or distally curved, 1-3.5(-4) cm x 2-3 mm, initially with a short beak; valves thinly coriaceous, glabrous or pubescent. Seeds ovoid or cuboid. Simpeteria.
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Discussion
Lotus strigosus, herein, includes L. strigosus and L. tomentellus of previous authors. The only annual Simpeteria, except possibly, Lotus intricatus, it is characterized by 1-2 flowered umbels that are short or long pedunculate. The key to annual species contrasts it with annual Microlotus with which it is sometimes confused. Beyond the features listed in the key following, the intergradient varieties commonly differ in seed shape, noted in discussion of Lotus strigosus var strigosus. The flowers are diverse in size, those of var tomentellus commonly being smaller than of var strigosus, and often scarcely open at anthesis. Petal shape is variable, seemingly at random. The keel is commonly broader than the wings in var strigosus, but usually not so in var tomentellus. Intermediates between vars strigosus and tomentellus may have a panduriform standard, characteristic of some other species of Simpeteria, but not otherwise observed in L. strigosus. Possibly the panduriform shape is a consequence of a complimentary gene action.
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Distribution
Pacific and sw United States and adjacent Mexico. Cismontane California from Yuba and Sonoma cos s, e across the deserts to e Arizona.
United States of America North America| Mexico North America|