California brome, Bromus carinatus var. carinatus, April–Oct, Native

California brome is a short-lived perennial, moderately tall to about 3 feet or more, and nodding. Side-to-side compressed florets open up (chevron pattern in illustration) as flowering progresses, a common grass transformation.

Frequently in partial shade, it also grows in full sun and in serpentine. Its leaves are slightly gray-green, mostly flat, and largely die-back in the summer. Leaf sheaths are either smooth or visibly soft-hairy. Florets disarticulate above the glumes, which are often seen on the old, standing culms.

Another tall perennial brome with strongly-keeled lemmas, B. catharticus, is a common campus weed has been found on the Preserve at the Dennis Martin site. It is distinguishable at arms-length by its very short awns (less than 3 mm) and smooth, dark-green stems. Another ruderal brome, B. stamineus, has been collected near the old lake bathhouse and the caretakers yard. It also has an open inflorescence, but unlike California brome and rescue brome, its branches are stiffly ascending. With a hand lens its broad (1 mm wide) transluscent lemma wings are apparent. It is said to accept summer water, remain green, and avoid summer dormancy.

Two varieties are recognized by FNA. Both have been vouchered for Jasper Ridge; var. marginatus is uncommon.

1. Most awns 8–17 mm long................................. var. carinatus

1. Most awns 4–7 mm long............................... var. marginatus

Name: ancient Gk name | keeled.