Snakeweed (matchweed, broomweed)

Gutierrezia sarothrae

Gutierrezia sarothrae is a perennial subshrub that ranges from 20 to 100 centimetres (7.9 to 39.4 in) in height. The stems are green to brown, bushy, and herbaceous, and branch upwards from a woody base. The stems die back during dormancy, giving the plant its broom-like appearance. They range from smooth to having some short hairs, and may be resinous and therefore sticky when touched. Dense clusters of small, yellow ray flowers form in clusters at the end of the stems from mid-July to September. As the stems are about the same length, this causes the plant to often appear domed or fan-shaped when flowering. The leaves are alternate and linear, and 5 to 60 millimetres (0.20 to 2.36 in) long and 1 to 3 millimetres (0.039 to 0.118 in) wide. The lower leaves are usually shed before the plant flowers. During its first year of growth, G. sarothrae produces a long, woody taproot, and numerous lateral roots as the plant matures.

The flowers of G. sarothrae are pollinated by various insects, resulting in an oval fruit covered with chaffy scales. The plant reproduces from seeds, which are light, densely hairy, and wind-dispersed. A single plant is capable of producing over 9000 seeds annually, although most ripe seeds fall beneath the parent plant. Seeds can remain viable in the soil for several years; under laboratory conditions seeds have remained viable for at least two years.