Depauperate Milkvetch

Hamosa bruceae (M. E. Jones) Rydb. Bull. Torrey Club 54: 323. 1927.
Astragalus lener Bruceae M. E. Jones, Rev. Astrag. 268. 1923.
A slender annual; stems less than 1 dm. high, sparingly strigose or glabrate, branched at the base, often reddish or purplish; leaves 3-5 cm. long, ascending; stipules broadly ovate, 2-3 mm. long; leaflets 6-9, mostly cuneate-obovate, deeply notched, 5-10 mm. long, strigose beneath, glabrate above; peduncles 3-5 cm. long, very slender; racemes short, 2-4-flowered ; bracts lanceolate, 1 mm. long; calyx black-hairy, the tube about 2 mm. long, the teeth subulate, 1 mm. long; corolla bluish-purple, 8 mm. long; pod falcate, lunate, 1.5-2 cm. long, 4 mm. wide and 3 mm. thick, glabrous, reticulate, purplish-mottled, sulcate on the lower suture, cordate in cross-section.
Type locality: Butte County, California. Distribution: Butte County, California.

Annual, Herbs, Taproot present, Nodules present, Stems erect or ascending, Stems or branches arching, spreading or decumbent, Stems less than 1 m tall, Stems solid, Stems or young twigs glabrous or sparsely glabrat e, Stems or young twigs sparsely to densely hairy, Leaves alternate, Leaves petiolate, Stipules conspicuous, Stipules membranous or chartaceous, Stipules persistent, Stipules free, Leaves compound, Leaves odd pinnate, Leaf or leaflet margins entire, Leaflets opposite, Leaflets 5-9, Leaflets 10-many, Leaves hairy on one or both surfaces, Inflorescences racemes, Inflorescence axillary, Bracts very small, absent or caducous, Flowers zygomorphic, Calyx 5-lobed, Calyx hairy, Petals separate, Corolla papilionaceous, Petals clawed, Petals blue, lavander to purple, or violet, Petals bicolored or with red, purple or yellow streaks or spots, Banner petal narrow or oblanceolate, Wing petals narrow, oblanceolate to oblong, Wing tips obtuse or rounded, Keel petals auriculate, spurred, or gibbous, Keel tips obtuse or rounded, not beaked, Stamens 9-10, Stamens diadelphous, 9 united, 1 free, Filaments glabrous, Style terete, Style persistent in fruit, Fruit a legume, Fruit tardily or weakly dehiscent, Fruit oblong or ellipsoidal, Fruit strongly curved, falcate, bent, or lunate, Fruit exserted from calyx, Fruit beaked, Fruit glabrous or glabrate, Fruit hairy, Fruit 3-10 seeded, Fruit 11-many seeded, Seeds cordiform, mit-shaped, notched at one end, Seed surface smooth, Seeds olive, brown, or black.

Astragalus pauperculus is an uncommon species of milkvetch known by the common name depauperate milkvetch. It is endemic to northern California, where it is known from the northern Sacramento Valley and the lowest reaches of the Cascade foothills adjacent. It grows in chaparral and vernally wet grassland habitat. This is a very small annual milkvetch which grows in a delicate mat with stems no longer than 10 cm (3.9 in). The leaves are a few centimeters long and are made up of small widely spaced leaflets. The inflorescence bears two to seven flowers which are purple, sometimes with paler colored edges on their petals. Each flower is generally less than 1 cm (0.39 in) long. The fruit is a crescent-shaped legume pod between 1 and 2 cm (0.39 and 0.79 in) long.