Sophora nuttalliana B.L.Turner
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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 - Low, pubescent, usually cinereous, perennial herb of subterranean origin from creeping roots and ascending, stipular rhizomes. Stems solitary or clustered, erect or ascending, branched below or (and) above, commonly bushy. Pubescence of subsinuous hairs .4-.8 mm, at first appressed and sericeous, then irregularly spreading. Leafstalk (3-)5-8 cm, short-petioled; leaflets (7-) 11-23, opposite or irregularly positioned, petioluled, ovate to oblanceolate, 5-15 mm, 2-3 r, usually longitudinally folded and appearing narrower and asymmetric, the glabrate upper surface commonly hidden. Stipules graduated; those of rhizomes glabrous, am-plexicaul sheaths; of stem base, pubescent, partially amplexicual; of medial stem, abortive. Racemes terminal on main axis and major branches, included or exsert-ed, 2-8 dm with 6-many, initially ascending, then spreading or descending flowers ca. 12-16 cm; bracts subulate, pilose, 3-4 mm. Pedicels 1-2 mm. Calyx gibbous, asymmetrically tubular, 5-8 mm with 5 subequal lobes 1-2 mm. Corolla white to ochroleucous; standard 17-18 mm, inserted separately from other petals and stamens, recurved 90°-150°, spatulate, the long claws basally hirsutulous; wings and keel subequal, ca. 14-15 mm, straight; keel acuminate-beaked. Filaments proximally swollen and pubescent above monadelphous base. Pistil stipitate 1 mm; ovary cylindric, pubescent; ovules 4-8; style short, slender. Fruits usually included because of stem growth after flowering; seed set commonly poor. Legume short-stipitate (or appearing long-stipitate if lower segments are sterile), irregularly moniliform; when immature, gray-villous, linear, without segmentation and with an acicular stylar beak; at maturity 5-7 cm, ca. 5 mm diam, sparsely pubescent to glabrate; segments tapering each direction or semiconfluent, usually only 2-3 maturing and variously separated by sterile intervals. Seeds (1-)2-4 (-6). Sophora.
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Discussion
S. sericea Nutt. (1818) non S. sericea Duhamel (1806); Patrinia sericea (Nutt.) Raf. (1819); Pseudosophora sericea (Nutt.) Sweet (1830); Vexibia sericea (Nutt.) Raf. (1832); S. nuttalliana Turner (1956). S. carnosa (Pursh) [sensu] Yakovlev (1967) non Astragalus carnosus Pursh (1814). Sophora nuttalliana is a low, uncomely legume of Astragalus-like aspect. The only herbaceous Sophora of its region, it is unmistakable if the segmented fruits are present, but in flower it is sometimes taken for an Astragalus, from which it is distinguished by its separate stamens. It is the most widely distributed of our native Sophora, and like its local relatives, S. leachiana and S. stenophylla, probably but remotely related to the woody species. The two groups of South Dakota stations are seemingly disjunct from the primary range of Sophora nuttalliana.
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Distribution
South Dakota, se Wyoming, s through Arizona and w Texas to adjacent Mexico; most common Kansas to Texas Panhandle. Diverse in habitat; most frequently of dry open, grassland plains and rocky hillsides; also canyon floors and creek beds, eroded badlands, and roadsides and other ruderal areas; usually in sand, sometimes gypsum, limestone-clay, igneous, or salt-flat soils; occasional or locally abundant. Ca. 1800-6700 ft. April (s)-June (n).
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