Common dogweed

Thymophylla pentachaeta, commonly called common dogweed, fiveneedle pricklyleaf or golden dyssodia, is a small perennial herb or subshrub in the Asteraceae family native to the arid and semi-arid regions of the southwestern and south-central United States, northern and central Mexico, and disjunctly in central Argentina. It grows on dry rocky slopes, gravelly flats, desert grasslands, mesas and roadsides, often on calcareous or alkaline soils. The plant forms a low, much-branched cushion 5 to 20 centimetres tall arising from a slender taproot and a slightly woody base. The opposite to alternate leaves are pinnately divided into three to seven needle-like, glabrous to slightly pubescent linear lobes about 1 to 1.5 centimetres long, dotted with conspicuous oil glands that emit a strong scent when crushed. The flower heads are borne singly on slender, naked, leafless peduncles 3 to 8 centimetres long; each head is about 13 millimetres across and consists of 8 to 13 short, bright yellow ray florets surrounding a denser disc of yellow tubular florets. The fruit is a small, dark, narrowly obconic achene crowned by a pappus of scales tipped with a single fine bristle. Flowering occurs from April through October.