Plants acaulescent or subacaulescent.
Roots elongate and slender taproots or irregularly thickened taproots divided into 2–5 elongate and slender taproots at base.
Caudices simple or 2–3-branched; basal leaf sheaths from previous years weathering into a few fibers or a sparsely chaffy or chartaceous thatch at base of pseudoscape.
Stems absent or 1–4 cm; pseudoscapes absent or < 2 cm.
Basal leaves glabrous or glaucous; primary leaflets ternate or pinnate, 0–2 secondary leaflet pairs along each rachis, laterals less than half central primary in length; secondaries ternate or pinnatifid (4–5-lobed); tertiaries absent; ultimate apical lobes suborbicular or obovate, 5–30 × 5–30 mm, margins erose, dentate, or serrate, teeth pungent, 3–5-lobed, central lobe entire or shallowly lobed, tips rounded, obtuse, truncate.
Cauline leaves 0–1, similar to basal.
Inflorescences peduncles 1–2, 10–40 cm, glabrous or glaucous; involucral bracts 0; rays 10–15, 2.5–6 cm, glabrous; involucel bractlets 2–6, linear or lanceolate, 3–10 × 0.3–1 mm, margins narrowly scarious or not; umbellets 20–30-flowered; pedicels 8–12 mm.
Flowers petals ochroleucous or yellow; anthers ochroleucous or yellow.
Fruits elliptic, suborbicular, 7–11 mm
, glabrous; body 3–4 mm wide; wings 1–2 mm, thin; vittae 2–3 in intervals, 9 on commissure.
2n=22.
Rocky slopes, open gravelly sites, chaparral or conifer forests, serpentine substrates. Flowering Apr–Jul. 300–1400 m. Sisk. CA. Native.
The broadest leaf forms of L. martindalei are often misidentified as L. howellii. Although their overall leaflet shapes are identical, the pungent-tipped teeth on the ultimate lobes of L. howellii are diagnostic and not present in any other species, which are at most mucronulate-tipped.