Member of the grass family. Grass flowers are smaller versions of regular flowers but without the petals. In Medusahead each floret (cluster of flowers) is made up of several individual flowers. Each seed has a long awn (needle-like end).

Medusahead is a gray-green grass found on mounds and outside the vernal pools. A few similar grasses occur at Mather Field, but none of them have really long awns (up to 2 inches) clustered together in a floret.

Medusahead is an annual grass. It germinates during the winter. It grows most quickly in the late spring when the weather warms. Medusahead blooms and sets seed in late May. 

Medusahead is a non-native plant introduced into California from Europe. It is very aggressive and easily competes with native plants. It is considered invasive in California.

Herbivores avoid eating it because of the high silica (rock) content. The fine rock crystals cause extra wear on their teeth.

Medusahead's high silica content also prevents the dead plants from decomposing (rotting) easily. In the field, can you find patches of last year's Medusahead? What grows in these patches of dead grass?