Fiveneedle Pricklyleaf

Perennials or subshrubs, ± grayish to green, to 15(–25) cm, usually puberulent to canescent, sometimes glabrescent or glabrous. Stems erect or spreading. Leaves mostly opposite; blades mostly pinnately lobed, 6–28+ mm overall, lobes 3–11 linear to filiform (usually stiff, setiform). Peduncles 20–100 mm, puberulent or glabrous. Calyculi 0, or of 1–5 deltate bractlets, lengths less than ¹/2 phyllaries. Involucres obconic to campanulate or hemispheric, 4–6 mm. Phyllaries 12–21, margins of outer distinct ¹/5 to nearly all their lengths, abaxial faces puberulent or glabrous. Ray florets (8–)12–21; corollas yellow to orange-yellow, laminae 2–6(–8) × 1–3 mm. Disc florets 16–40 or 50–80; corollas yellow, 2–4 mm (tending to zygomorphy in peripheral florets in some plants). Cypselae 2–3 mm; pappi of 10 erose and/or aristate scales mostly 1–3 mm.

Hymenatherum pentachaetum de Candolle in A. P. de Candolle and A. L. P. P. de Candolle, Prodr. 5: 642. 1836; Dyssodia pentachaeta (de Candolle) B. L. Robinson

Thymophylla pentachaeta (DC.) Small, Fl. SE. U. S. 1295
1903.
Hymenatherum pentachaelum DC. Prodr. 5: 642. 1836.
Dyssodia pentachaeta B. L. Robinson, Proc. Am. Acad. 49: 507. 1913.
A low puberulent perennial, suffruticose at the base, usually less than 1 dm. high; stems with many short branches, rather densely pilose-puberulent; leaves mostly opposite, crowded, 1-2 cm. long, pilose-puberulent, pinnatifid, with 5-7 short, stiff, spinulose-tipped divisions; peduncles 3-5 cm. long; involucre turbinate-campanulate, 4-5 mm. high and about as broad, naked or with 1-3 minute subulate accessory bracts; principal bracts united high up, in two series, the inner with triangular erose tips and 2-5 glands, the outer narrowly linear, with the ciliate free margins decurrent to near the base; ligules 3 mm. long, 1.5 mm. wide; disk-corollas 2.5 mm. long; tube shorter than the trumpet-shaped throat; achenes nearly 3 mm. long, glabrous; pappus double; inner 5 squamellae lanceolate, nearly 3 mm. long, including the awn, the outer 5 oblong-spatulate, 1 mm. long.
Type locality: Monterey, Nuevo Leon. Distribution: Texas to Arizona and Nuevo Leon.

Thymophylla pentachaeta, also known as fiveneedle pricklyleaf, golden dyssodia or dogweed, is a perennial or subshrub in the family Asteraceae. The species is native to the southwestern United States and Mexico.

Four varieties are recognised:

Thymophylla pentachaeta var. belenidium Thymophylla pentachaeta var. hartwegii Thymophylla pentachaeta var. pentachaeta Thymophylla pentachaeta var. puberula