Peirson’s serpentweed

Haplopappus eximius H. M. Hall subsp. peirsonii D. D. Keck, Madroño 5: 169. 1940; H. peirsonii (D. D. Keck) J. T. Howell; Tonestus peirsonii (D. D. Keck) G. L. Nesom & D. R. Morgan

Perennials, cespitose, 5–20 cm; with branched, woody caudices surmounting taproots. Stems (clothed with marcescent leaf bases) glabrous, densely stipitate-glandular. Leaves: basal blades broadly spatulate, 30–80 × 12–25 mm; cauline blades oblong to linear, 28–42 × 7–11 mm, reduced distally; 1- or 3-nerved, margins coarsely and irregularly serrate to (distal) nearly entire, stipitate-glandular, faces glabrous, stipitate-glandular. Heads radiate, usually borne singly, sometimes 2–4. Peduncles 8–24 mm. Involucres broadly campanulate, (14–)19–28 × (12–)14–20 mm. Phyllaries 19–31(–44) in 3–4 series, 1- or weakly 3-nerved, ± equal, margins eciliate; outer and mid green, oblong, 10–12 × 2–4.5(–7) mm, foliaceous, apices obtuse to acute, faces stipitate-glandular; inner usually green, sometimes anthocyanic, linear, 10–12.5 × 1–2.5 mm, chartaceous proximally, margins scarious, fimbriate and/or stipitate-glandular distally, apices acute to acuminate, faces stipitate-glandular distally. Ray florets 16–20; laminae elliptic, 6.5–8 × 1.5–2.5 mm. Disc florets 44–63, barely exceeding involucres; corollas narrowly funnelform, 7.5–10.5 mm, lobes erect, 0.7–1.7 mm, lengths ¹ / 10 – ¹ / 5 corollas; anthers 3.3–3.8 mm; style-branch appendages subulate, 1.3–2.5 mm, stigmatic lines ca. 1.5 mm. Cypselae linear, 2.5–6 mm, 6–9-nerved, faces strigose to villous, often ± viscid; pappus bristles ± 30, brittle. 2n = 90.

Flowering and fruiting early–late summer. Crevices of granitic outcrops, talus slopes, in alpine and sub-alpine communities; 2900–3700 m; Calif.

Lorandersonia peirsonii is known only from the upper elevations of the central Sierra Nevada and from collections in the western Great Basin, in northeastern Fresno, northwestern Inyo, and southern Mono counties, California.