Plants acaulescent.
Roots elongate and slender taproots.
Caudices simple or 2–3-branched, subterranean; basal leaf sheaths from previous years weathering into a thatch of fibers or chartaceous scales at base of pseudoscape.
Stems absent; pseudoscapes absent or 1–3 cm, subterranean, obscured by leaf sheaths.
Basal leaves glabrous, glabrate, or sparsely pubescent on abaxial surface or along midveins; primary leaflets pinnate, 4–6 secondary leaflet pairs along each rachis, laterals half to subequal to central primary in length; secondaries pinnatifid; tertiaries entire or pinnatifid (2–5-lobed); ultimate apical lobes elliptic or oblong, 2–3.4 × 0.7–1 mm, tips acute, apiculate, or mucronulate.
cauline leaves 0.
Inflorescences peduncles 1–2, 10–30 cm, glabrous or glabrate; involucral bracts 0; rays 2–12, 1–3 cm, glabrous; involucel bractlets 0–2, 2–3 × 0.1–0.2 mm, margins not scarious; umbellets 10–20-flowered; pedicels 2–8 mm.
Flowers petals white or purple; anthers ochroleucous or white.
Fruits oblong, obovate, or obelliptic, 7–14 mm
, glabrous; body 2–4 mm wide; wings 1–2 mm, thin; vittae 1–2 in intervals, 2–6 on commissure.
2n=22.
Gravelly or rocky serpentine slopes in conifer forests. Flowering May–Aug. 700–1400 m. Sisk. CA. Native.
This species is often confused with L. tracyi. The pedicel length in each of the two species is more variable than reported in previous floras, and L. engelmannii has been found to have involucel bractlets in some individuals. The flowers in L. tracyi are yellow while those in L. engelmannii are white or purple.