Kern Canyon False Goldenaster

Known only from the lower Kern River Canyon, Kern County, Heterotheca shevockii is distinguished from other species by its usually tall stems and lanceolate-triangular mid cauline leaves with usually revolute margins, its large heads and floral parts, and pappi bristles usually only about 90% the length of the disc corollas at flowering. Smaller plants are similar to H. villosa var. scabra, known in California from a few locations in the Little San Bernardino Mountains (1200–1300 m).

Perennials, (28–)50–131 cm; taprooted. Stems 1–35+, ascending to erect (sometimes brown proximally, sometimes ± brittle), sparsely strigose, moderately hispid (hairs often broken off in older stems), distally sparsely hispido-strigose and densely stipitate-glandular, abundantly long-hirsute. Leaves: proximal cauline subpetiolate to sessile, blades oblanceolate to lanceolate, 25–55 × 5–16 mm, bases convex-cuneate, margins entire, strigoso-ciliate, proximally long-ciliate, apices acute, mucronate, faces moderately hispido-strigose; distal blades sessile, linear-lanceolate to lanceolate-triangular, (17–)31–65 × 6–15 mm, reduced distally, bases abruptly convex-cuneate or rounded to sometimes subclasping, margins entire, usually revolute, faces sparsely to moderately long-hispido-strigose proximally, moderately to densely stipitate-glandular (branch leaves much reduced distally, linear to linear-oblanceolate). Heads (3–)5–20(–70) in paniculiform arrays, branches elongate on robust shoots. Peduncles 10–60+ mm, sparsely hispido-strigose, densely stipitate-glandular; bracts 3–10, proximal leaflike, greatly reduced distally, linear to linear-oblanceolate, distalmost phyllary-like (not surpassing heads). Involucres cylindro-turbinate to campanulate, 9–13 mm. Phyllaries in 5–6 series, unequal (outer lengths ¹ / 5 – ¹ / 4 inner), faces sparsely strigose especially along pronounced midnerves, densely stipitate-glandular. Ray florets 9–15(–18); laminae 5–8(–10) × 0.8–2 mm. Disc florets (31–)40–70(–80); corollas barely ampliate, 5–7 mm, tubes and throats sparsely strigose, lobes 0.3–0.8(–1.1) mm, lobes glabrous or sparsely strigose (hairs 0.04–0.27 mm). Cypselae monomorphic, obconic, compressed, 2–4.5 mm, ribs 8–12, faces moderately strigose; pappi off-white, outer of linear scales 0.25–1 mm, inner of 35–45 bristles 5–7 mm, longest weakly clavate (usually equaling or shorther than corollas). 2n = 36.

Heterotheca villosa (Pursh) Shinners var. shevockii Semple, Phytologia 73: 453. 1993

Heterotheca shevockii is a rare species of flowering plant in the family Asteraceae known by the common names Kern Canyon false goldenaster and Shevock's goldenaster. It is endemic to California in the United States, where it is known only from Kern County. It grows along a 21-mile stretch of the Kern River.

Heterotheca shevockii is a perennial herb growing 28 to 131 centimeters (11.2-52.4 inches) in height, often with many erect stems. The stems are hairy to bristly. The lance-shaped leaves are up to 6.5 centimeters (2.6 inches) long by 1.6 cm (0.64 inches) wide. The inflorescence contains 3-70 flower heads borne on hairy, glandular peduncles. Each head contains up to 18 yellow ray florets each up to a centimeter long, and many disc florets at the center. The fruit is an achene which may be over a centimeter (>0.4 inches) long including its pappus. Flowering occurs mostly in August and September, but it may be seen in flower between January and November.

Heterotheca shevockii grows in chaparral and woodland habitat in sandy soils in crevices and ditches near the river. There are about 8 known populations of this plant, totalling 246 individuals.