Taeniatherum caput-medusa is an annual grass that is 8-24 in. (20.3-61 cm) tall and has distinct bristly seed heads and few leaves.
Foliage
Leaves are less than 0.13 in. (0.32 cm) wide. One or more stems arise from the base of the plant and can be as much as 2 ft. (0.6 m) tall. Each stem produces a single, short, spike-type seed head.
Flowers
Flowering occurs in late spring, when flower heads develop at the apex of the stems. Flowering occurs in late spring and early summer.
Fruit
The seed heads are what distinguish this plant from other annual grasses. Awns twist as they dry, hence the common name "medusahead". The longer of the two awns in each spikelet is barbed. These barbs catch on fur or clothing and spread seed.
Ecological Threat
T. caput-medusa was first collected in Oregon, in 1887. Plants invade dry, open lands with frequent disturbance such as fields and pastures. It is native to the Mediterranean.