Taeniatherum caput-medusae

Medusahead adult
Medusahead is an annual growing from six inches to two feet high. Flowering and seed production take place in late spring and early summer.
Medusahead seedling
Leaf blades are about one-eighth inch wide.
Weed Infestation
Medusahead infestation
Medusahead was brought to the United States from Eurasia. It is extremely competitive completely displacing other desirable grass species. It spreads by seed commonly carried by wind, animals, clothing, and vehicles.
Medusahead seedhead
It is sometimes confused with foxtail barley or squirreltail, but is different in that the seedhead doesn't break apart completely as the seeds mature.
Twisted Awns
Medusahead twisted awns
Awns of the seedhead are long and become twisted as the seed matures.