Acmispon strigosus |
Acmispon rigidus |
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strigose lotus |
broom lotus, desert lotus, hairy lotus |
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Habit | Herbs, annual, usually mat-forming, sometimes cespitose (ascending and bushy), green to grayish, 0.3–5 dm, not or ± fleshy, strigillose, hirsute, canescent-tomentose, or scantily pubescent; taprooted. | Subshrubs, bushy, green, (2–)3–9(–15) dm, not fleshy, sparsely strigose to glabrate; from woody caudices. | ||||||||
Stems | 1–20+, procumbent or decumbent to ascending, branched basally, herbaceous, slender, leafy. |
1–30+, ascending, branched (distal branches ± flexuous and herbaceous), stiff (± woody), remotely leafy. |
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Leaves | irregularly pinnate; stipules glandlike; subsessile; rachis 3–20 mm, flattened; leaflets 4–10, blades unequal, obovate to oblanceolate to linear-oblong or oblong, apex acute to obtuse or truncate, surfaces ± densely tomentose to glabrate. |
irregularly pinnate or palmate; stipules evanescent, glandlike, ovoid-deltoid; short-petiolate or sessile; rachis 0–5 mm, not flattened; leaflets 3–5, blades obovate to oblanceolate, apex obtuse to emarginate, surfaces strigose. |
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Inflorescences | 1–3-flowered. |
1–4(or 5)-flowered. |
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Peduncles | ascending or reflexed, upturned, 3–25 mm, shorter to longer than leaves (often elongated in fruit); bract absent or 1–3-foliolate, usually subtending umbel. |
ascending to erect, slender, often flexuous, 20–60(–130) mm, much longer than leaves; bract absent or unifoliolate, subtending umbel. |
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Flowers | (5–)6–10(–12) mm; calyx 3–5.5 mm, tube ± sparsely strigillose or glabrous, lobes subulate; corolla yellow (sometimes banner orangish abaxially), turning orange or reddish, claws ± equaling calyx tube, banner implicate-ascending or remaining closely implicate, wings longer than keel; style corneously thickened, marked by color, straight, puberulent or glabrous. |
12–20(–24) mm; calyx 6.5–10 mm, tube ± densely strigillose, lobes subulate, abaxial pair sometimes connate behind banner; corolla yellow, sometimes ± suffused with red or orange, banner often red-backed, claws ± equaling calyx tube, banner remaining implicate, ± ascending to 45°, wings longer than keel; style corneously thickened and laterally grooved proximally, straight, glabrous. |
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Legumes | persistent, exserted, erect or divergent, brown, straight to ± curved distally, compressed, not or slightly constricted, incompletely septate, linear-oblong, 10–35 × 2–3 mm, thinly leathery, apex initially short-beaked, dehiscent, smooth, margins smooth, thin, glabrous or ± strigose. |
persistent, exserted, erect or divergent, yellow-brown to reddish, straight, turgid, not constricted, not septate, linear-oblong to oblong, 20–40(–45) × 3–5 mm, leathery, apex short-beaked, dehiscent, smooth, margins smooth, keeled, usually glabrate, rarely sparsely strigillose. |
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Seeds | 5–10, greenish to brown, ± mottled, ovoid to cuboid or globose, rugulose or granular. |
18–30, light brown, ± mottled, subglobose, finely granulose or papillose. |
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2n | = 14. |
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Acmispon strigosus |
Acmispon rigidus |
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Phenology | Flowering late winter–spring. | |||||||||
Habitat | Washes, rocky hillsides, talus and cliff-ledges of desert canyons, shrubby grasslands, scrub, oak chaparral, pinyon woodlands, Joshua tree woodlands, roadsides, on granite, limestone, or lava. | |||||||||
Elevation | 10–1400(–1600) m. (0–4600(–5200) ft.) | |||||||||
Distribution | sw United States; n Mexico |
AZ; CA; NV; UT; Mexico (Baja California, Sonora) |
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Discussion | Varieties 3 (3 in the flora). D. Isely (1981) discussed the variation in Acmispon strigosus (as Lotus), distinguishing three varieties, two rather distinct but with intergrading phases, and one apparently more transitional, although distinct enough to be recognized. These varieties were only noted for California in recent treatments (for example, L. Brouillet 2012, following D. Isely 1993). Nonetheless, the typical (for example, excluding intergrading phases) varieties represent recognizable morphologies that also have geographic distinction. Specimens representing intergradation seem to occur throughout the range of overlap of these varieties, sometimes rendering determination difficult. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Acmispon rigidus occurs in the Californian Transverse Ranges to the Mojave and Sonoran deserts, into central Arizona, southern Nevada, and Washington County, Utah. It is reported to hybridize with A. plebeius, A. argyraeus (variety not specified), A. mearnsii var. mearnsii, A. neomexicanus (also reported by D. Isely 1981), A. utahensis, A. wrightii (also reported by Isely), and possibly with A. grandiflorus var. grandiflorus (as var. mutabilis Ottley) (A. M. Ottley 1944). (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 11. | FNA vol. 11. | ||||||||
Parent taxa | Fabaceae > subfam. Faboideae > Acmispon | Fabaceae > subfam. Faboideae > Acmispon | ||||||||
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Subordinate taxa | ||||||||||
Synonyms | Hosackia strigosa, Anisolotus strigosus, Lotus strigosus, Ottleya strigosa | Hosackia rigida, Anisolotus argensis, A. rigidus, Lotus argensis, L. rigidus, Ottleya rigida | ||||||||
Name authority | (Nuttall) Brouillet: J. Bot. Res. Inst. Texas 2: 392. (2008) | (Bentham) Brouillet: J. Bot. Res. Inst. Texas 2: 392. (2008) | ||||||||
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