Lepidium flavum
in War Department [U.S.], Pacif. Railr. Rep. 4(5): 67. 1857.
Annuals; glabrous. Stems few to several from base, prostrate or decumbent, branched, (0.2–)0.4–3(–4.6) dm. Basal leaves rosulate; petiole (0.3–)0.6–2.5(–3.2) cm; blade spatulate to oblanceolate or linear, pinnatifid or lobed (lobes 3–9 pairs, ovate to oblong), (0.7–)1.3–5.2(–6) cm × 3–8 mm, margins (of lobes) entire. Cauline leaves: petioles 0.1–0.5 cm; blade obovate to spatulate or oblanceolate, (0.6–)1–1.8(–2.3) cm × 2–8(–14) mm, base attenuate-cuneate, not auriculate, margins dentate-sinuate to crenate orentire. Racemes (corymbose to subcapitate), slightly elongated in fruit; rachis glabrous. Fruiting pedicels divaricate to horizontal, straight or slightly sigmoid, (terete), (2.7–)3–4.4(–5) × 0.2–0.3 mm, glabrous. Flowers: sepals obovate-oblong, 1–2 × 0.6–1 mm; petals yellow (rarely creamy white at early anthesis), spatulate, (1.8–)2–2.8(–3) × 0.6–1 mm, claw 0.5–1 mm; stamens 6; filaments (median pairs) 1.2–2 mm, (glabrous); anthers 0.4–0.5 mm. Fruits usually narrowly to broadly ovate, rarely suborbicular, (2.2–)2.5–3.8(–4.2) × (1.6–)2.2 3.2(–3.5) mm, apically divergently winged, apical notch 0.2–0.6 mm deep; valves thin, smooth, moderately reticulate-veined, usually glabrous, rarely pubescent; style 0.7–1.6 mm, exserted beyond apical notch. Seeds ovate, 1–1.6 × 0.6–0.9 mm. 2n = 32.
Phenology: Flowering Mar–Jun.
Habitat: Sagebrush communities, open mesas, sandy flats and deserts, alluvial fans, dry valley floors, floodplains, washes, alkaline flats, roadsides, playa margins
Elevation: 600-1600 m
Distribution
Calif., Nev., Mexico (Baja California).
Discussion
The slightly smaller-fruited form of Lepidium flavum, recognized by C. L. Hitchcock (1936) and R. C. Rollins (1993) as var. felipense, does not merit recognition.
Selected References
None.