Erect or spreading annual growing in dense subshrub-like clusters. Stinknet is identified by its sharp odor, its yellow flower heads resembling tiny golf balls that grow singly or in clusters at the stem tips and its very divided small dark green leaves.
Plants pungently scented, 6 to 18 inches tall, stems branching from the base or throughout; leaves 2 to 3 times pinnately dissected, lobes narrow; flower heads globe-like, solitary or in clusters of 2 to 4, showy, yellow, disc flowers only.
Habitat
Found in sandy and gravelly soils in washes, river bottoms, waste grounds, disturbed areas, along roadsides, major highways, vacant lots, cracks in pavement and sidewalks and agricultural field edges. It often competes with and displaces native species.
Flower Characteristics
Globe-like flower head consists of only tube-like flowers (disc florets) each 4-lobed and 1/16 inch long. Each flower head can have as many as 250+ florets. Below the flower head is a whorl of leaf-like bracts, each bract 1/8 inch long and 1/4 inch wide.
Leaf and Stem Characteristics
Dark green leaves are 3/4 to 1-1/2 inches long, about 1/16 inch wide and are highly dissected into narrow segments. They are covered with very small stiff hairs or a sparse amount of very fine soft hair and dotted with tiny glands.
Fruit and Seed Characteristics
Fruit is cylinder-shaped or 4 angled and ribbed, less than 1/16 inch long, has a slight curve and is sparsely dotted with very small glistening oil glands. Tiny hair-like bristles (pappi) form a smooth to slightly pointed narrow crown at the fruit top.
Dry mature seed heads are brittle and shatter into dusty pieces loaded with thousands of tiny seeds less than 1/16 inch. Seeds germinate in about 10 days allowing stinknet to spread easily and quickly.