Bromus sitchensis Trin.
Alaska brome
Robust, erect, perennial tufts, 90-150 cm, with wide, bright green leaves. Leaf-sheath glabrous apart from a few hairs at margins just below ligule, green, becoming brownish or purplish. Ligule 3-3.5 mm, denticulate, abaxially with long hairs near margins. Leaf-blade 18-25 cm × 5-12 mm, abaxially minutely scabrid on nerves, adaxially smooth, margins extremely finely scabrid, sometimes with a few scattered hairs. Culm erect, internodes smooth, but finely scabrid just below panicle. Panicle 20-30 cm, with erect, scabrid branches, lower branches later spreading, becoming reflexed. Spikelets 4-5 cm, 7-10-flowered, linear, green to purple-suffused, rachilla exposed at maturity. Glumes subequal, acute to acuminate, smooth, with scabrid keel; lower c. 12 mm, 3-5-nerved, upper c. 13 mm, 7-9-nerved. Lemma 14-16 mm, 7-9-nerved, keeled, very minutely scabrid to almost smooth, keel minutely scabrid, sometimes keel and flanks with a few scattered, minute hairs near base; awn 4.5-9 mm. Palea very slightly < lemma. Callus with minute hairs. Rachilla scabrid to minutely pubescent. Anthers 0.4-0.5 mm in cleistogamous flowers, 3-5 mm in chasmogamous flowers. Caryopsis c. 7 × 1.5 mm.
S.: Canterbury. Waste ground and gardens.
Naturalised from North America.
Bromus sitchensis frequently becomes heavily rust-infected whereas species in sect. Ceratochloa naturalised from South America are not susceptible (A. J. Healy in litt.).
