Lotus oblongifolius (Benth.) 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 - Robust or tenuous, pubescent or glabrate, sprawling or ascending perennial from slender rootstocks, 1-6 dm. Pubescent of fine hairs ca. .2-.3 mm, these appressed, straight, slightly sinuous, or puberulent-incurved. Leaves subsessile or lowermost long-petioled; leafstalk (1 —) 1 —2.5(—3) cm, 1.5-8 r, frequently polymorphic, those of lower leaves ca. 2-3 r, ranging upwards to 4-7 r. Stipules scarious, usually broken and inconspicuous at maturity. Umbels peduncled 1-10 cm, usually exserted, subtended by a simple or trifoliolate bract, or bract absent, with 1-6 flowers 8-13 mm. Pedicels .5-1.5 mm. Calyx tube 2.5-3.5 mm, teeth 1.5-3 mm. Corolla whitish-yellow, or dully bicolored, the standard yellow, purple-veined or turning reddish. Wings and keel white, their claws often slightly exserted from calyx; keel tip yellow and subacute. Ovary with (5-) 10-13 ovules. Legumes clustered, variously directed, turgid, 2.5-5 cm x 1.5-2 mm, dehiscent; valves coriaceous, brown. Seeds few. Hosackia.
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Discussion
Among Lotus with evident stipules, L. oblongifolius has an umbel-subtending bract, comparatively short petal claws, short pedicels, and calyx lobes that frequently approximate the tube. Its foliage is diverse in leaflet proportions. Recent floristic summaries (Munz, 1959; Abrams, 1944; Porter, 1957) follow Ottley (1923) in considering it to include two or three varieties or species. These include the northern phase, commonly called Lotus or Hosackia torreyi, which has broader and more obtuse leaflets and looser pubescence than the southern ones, L. oblongifolius. L. cupreus is a local, heavily rooted ecotype from upper elevation of the Sierra Nevada (Tulare co). The species is more complex than these cited treatments imply. The plants of the northern Sierra, Cascades and Coast Ranges are commonly robust with elliptic midstem leaflets ca. 2-2.6 r. The leaves are slightly dimorphic, the lower having broader, more obtuse leaflets than the upper. Pubescence is evident and persistent. Although these include ideal Hosackia torreyi, they are not of one type and merge insensibly into the heterogenous southern forms. In the southern Sierra to Kern co, pubescent plants with mostly acute leaflets, ca. 3 r, are most common. The Transverse Ranges boast races (L. lathyroides, Hosackia oblongifolius var angustifolia and L. torreyi var seorsus) that, in ideal form, as in the San Gabriel Mts., are of glabrate plants with strikingly dimorphic foliage, the leaflets ranging from 2-4 r below to 8 r above. Ottley (1923) has suggested that the extremes are first-year plants. If so, this growth sequence is regionally restricted. The L. lathyroides form is again present in the San Bernardino Mts., but the plants are pubescent and some have leaflets ca. 4 r; those of representatives of the South Coastal and Peninsular ranges are 4-6 r. Plants east of the mountains to Nevada include a mixture, some of which approach the distant San Gabriel (L. lathyroides) populations. Among all of these, the leaves may be dimorphic or not. Ottley’s (1923) Lotus oblongifolius var cupreus is listed following. No simple varietal segregation of the remainder seems possible.
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Distribution
Southern Oregon to Mexico.
United States of America North America| Mexico North America|