Astragalus jejunus
Botany (Fortieth Parallel), 73, plate 13, figs. 1–6. 1871.
Plants densely clump-, cushion-, or tuft-forming, 1–5 cm, strigulose; from superficial much-branched caudex, branches covered with thatch of marcescent leaf rachises. Stems obscured by stipules and leaf bases. Leaves erect, 1–4 cm; stipules 1.5–3 mm, membranous becoming papery; leaflets 9–15(or 17), blades linear to narrowly elliptic, 1–5 mm, apex obtuse to acute, surfaces strigose; terminal leaflet often decurrent distally, not jointed to rachis. Peduncles erect, 0.5–3.5 cm, together with racemes subequal to or ± surpassing leaves. Racemes 3–7-flowered, flowers spreading; axis 0.2–1 cm in fruit; bracts 1–1.5 mm; bracteoles 0. Pedicels 1–2.5 mm. Flowers 5–6.5 mm; calyx 2.3–3 mm, strigose, tube 1.5–2 mm, lobes subulate, 0.5–1 mm; corolla pink-purple or white; keel 3.7–4.4 mm. Legumes green with purple mottling, slightly curved, subglobose, 10–17 × 7–11 mm, papery-membranous, strigose. Seeds 10–14.
Phenology: Flowering May–Jul.
Habitat: Sagebrush and sagebrush-juniper or pinyon-juniper communities, windswept ridgetops.
Elevation: 1700–2400 m.
Distribution
Colo., Idaho, Nev., Utah, Wyo.
Discussion
Astragalus jejunus is a tufted plant that produces masses of small, inflated fruits, usually gaily mottled with reddish purple, nestled amid broomlike clusters of leaf rachises.
Plants with articulated terminal leaflets and pale flowers from Big Horn County, Wyoming, form the basis of var. articulatus. Whether such plants constitute a distinct taxon or merely recurrent expression of variable phenotypes requires additional research. Both of the critical differences are encountered occasionally in other populations.
Selected References
None.