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- Grass Family: Poaceae
Medusahead
(Taeniatherum (=Elymus) caput-medusae)
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Medusahead is a winter annual grass native to Europe. It reduces the amount of desirable forage on rangeland. Plants contain high amounts of silica making it unpalatable for livestock. In addition, the sharp, barbed awns can injure the face and mouth parts of grazing animals. Dead plants create a thick thatch taking two or more years to decompose, disturbing natural cycles of nutrients and other plants while fueling wildfires. In California the weed inhabits central and northern portions of the state up to 6900 feet (2100 m).
Habitat
Disturbed sites, grasslands, rangelands, and oak woodlands. The weed thrives in areas receiving at least 9 inches (23 cm) of rain per year or clay soils where deep soil moisture is available late in the growing season.
Seedling
Seedlings remain attached to the long-awned floret. Leaf blades are very narrow, 1/50 inch (0.5 mm) wide. If the primary root dries out, the seedling can develop a secondary root when moisture becomes available.
Mature plant
Mature plants form small, loose bunches of stems that are 6 to 12 inches tall (15–30 cm), sometimes up to 2 feet (0.6 m). Leaves, typically 2 to 4 per stem with 9 veins, are 4 to 12 inches (10–30 cm) long, and 1/25 to 1/8 inch (1–3 mm) wide. Medusahead matures later and thus stays greener later in the season than other annual grasses.
Collar region
Where the leaf meets the stem there is a tiny ligule and hairless auricles.
Flowers
The flowering head is a spike that is 9/16 to 2 inches (1.5–5 cm) long excluding awns. Awns are the most prominent feature; they are attached to the seeds and may be as long as 2 inches (5 cm), barbed, and rough to the touch. Spikelets are stalkless with awnlike glumes fused at the base. Lanceolate lemma are present that are 3/16 to 5/16 inches (5–8 mm) long, 3-veined, and hard. There are 2 florets per spikelet.
As the spike matures, the main axis stays intact and often bends in an almost horizontal position. As seeds drop from the head, the spike “skeletons” often stay on the plant.
Reproduction
Reproduces by seed. Soil seed life is typically two to three years.
