Bromus tectorum L.

cheatgrass, downy brome


Info

Subfamily: Pooideae
Genus etymology: Bromus = "food" [Greek] the ancient name for oats (Avena)
Species etymology: tectorum = "roof" [Latin] refering to growing on roofs, although this is not the usual habit of the grass
Photosynthetic type: C3 (cool season)
Nativity: naturalized - accidental
First recorded in Hawaiʻi: 1933

Map

 Distribution of Bromus tectorum in Hawaiʻi.

Inflorescence

Bromus tectorum Inflorescence
Bromus tectorum Inflorescence

Spikelets

Bromus tectorum Spikelets
Bromus tectorum Spikelets
Bromus tectorum Spikelets
Bromus tectorum Spikelets

Description

Plants annual. Culms 5-90 cm, erect, slender, puberulent below the panicle. Sheaths usually densely and softly retrorsely pubescent to pilose, upper sheaths sometimes glabrous; auricles absent; ligules 2-3 mm, glabrous, obtuse, lacerate; blades to 16 cm long, 1-6 mm wide, both surfaces softly hairy. Panicles 5-20 cm long, 3-8 cm wide, open, lax, drooping distally, usually 1-sided; branches 1-4 cm, drooping, usually 1-sided and longer than the spikelets, usually at least 1 branch with 4-8 spikelets. Spikelets 10-20 mm, usually shorter than the panicle branches, sides parallel or diverging distally, moderately laterally compressed, often purplish-tinged, not densely crowded, with 4-8 florets. Glumes villous, pubescent, or glabrous, margins hyaline; lower glumes 4-9 mm, 1-veined; upper glumes 7-13 mm, 3-5-veined; lemmas 9-12 mm, lanceolate, glabrous or pubescent to pilose, 5-7-veined, rounded over the midvein, margins hyaline, often with some hairs longer than those on the backs, apices acuminate, hyaline, bifid, teeth 0.8-2(3) mm; awns 10-18 mm, straight, arising 1.5 mm or more below the lemma apices; anthers 0.5-1 mm. 2n = 14.
(Description source: Barkworth, M.E., Capels, K.M. & Long, S. (eds.) 1993. Flora of North America, north of Mexico. Volume 24. Magnoliophyta: Commelinidae (in part): Poaceae, Part 1. Oxford University Press, New York. 911 pp. http://floranorthamerica.org/Bromus_tectorum )