Bromus pacificus
Bromus pacificus, the Pacific brome, is a perennial grass native to the Pacific coast of North America. Bromus pacificus has a diploid number of 28.
Taxonomy
Bromus pacificus is often misidentified as various species of Bromus sect. Ceratochloa, including B. carinatus and B. sitchensis. B. pacificus resembles these species with its large and open panicles, but its lemmas are rounded or slightly keeled as compared to the flattened lemmas of B. sect. Ceratochloa. In addition, B. pacificus typically occurs only near the coast of British Columbia while species of B. sect. Ceratochloa are more widely distributed, including habitats in California where B. pacificus has been misidentified.
Description
Bromus pacificus lacks rhizomes and grows tall. The smooth culms are wide at their base and have five to nine nodes. The brownish culms are relatively pubescent, with hairs up to long, though culms are occasionally glabrous with hairs only adjacent to nodes. The leaf sheaths remain closed for most of their length, being open for only. Leaf sheaths are glabrous or pilose with hairs long, and lack auricles. The membranous and glabrous ligules are long. Leaf blades are long and wide, with an adaxial surface covered with hairs up to long and a glabrous abaxial surface. Margins are smooth or slightly serrated. The open panicles are long and wide, with spreading or nodding branches. The spikelets are long and number one to six per branch. The rachillas can sometimes be visible at maturity. Spikelets have six to eight florets. Glumes are pubescent, with hairs up to long. The one-nerved lower glumes are long, and the three-nerved upper glumes are long. The seven-nerved lemmas are long and wide, and are covered with appressed hairs up to long. Awns are long. Paleas are typically shorter than lemmas, being long, with dense cilia up to long. The dark brown anthers are long.
Distribution and habitat
Bromus pacificus occurs along the Pacific coast as its specific epithet indicates. It occurs from southeastern Alaska down to central Oregon; most often it occurs in the coast of British Columbia. Habitats include moist ravines, shaded forests, wet thickets, saline beaches, ditches, and road verges, from in elevation.