Bromus tectorum |
Bromus orcuttianus |
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cheatgrass, downy brome, downy chess |
Orcutt's brome |
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Habit | Plants annual, 5–90 cm tall. | Plants perennial, 90–150 cm tall; loosely cespitose. |
Culms | puberulent. |
internodes glabrous to pubescent, pilose to densely pubescent below the nodes; nodes 2–4, pubescent or puberulent. |
Leaves | sheaths densely and softly retrorsely pubescent to pilose; upper sheaths sometimes glabrous; blades 1–16 cm × 1–6 mm, softly hairy on both surfaces. |
sheaths sparsely to densely pilose; basal sheaths with hairs 2–4 mm, occasionally glabrous; upper sheaths with hairs to 1 mm; collars pilose with hairs to 4 mm or glabrous; ligules 1–3 mm; blades 7–24 cm × 3–12 mm; flat, glabrous, sometimes hairy. |
Inflorescences | 5–20 × 3–8 cm; open, nodding; branches 1–4 cm, drooping, 1-sided and longer than the spikelets, usually at least 1 branch with 4–8 spikelets. |
7–13.5 × 2–12 cm; branches erect or ascending, appressed to slightly spreading. |
Spikelets | 10–20 mm, moderately laterally compressed, not densely crowded, 4–8 florets. |
20–40 mm, elliptic to lanceolate; terete to moderately laterally compressed, with 3–9(11) florets. |
Glumes | villous, pubescent, or glabrous; lower glumes 4–9 mm, 1-veined; upper glumes 7–13 mm, 3–5-veined. |
glabrous, occasionally scabrous or pubescent; lower glumes 5–9 mm, 1(3)-veined; upper glumes 7–11 mm, 3(5)-veined, sometimes short-pointed. |
Lemmas | 9–12 mm, lanceolate, glabrous or pubescent to pilose, 5–7-veined; tips acuminate; hyaline; bifid, with teeth 0.8–2(3)mm, awned; lemma awns 10–18 mm; straight. |
9–16 mm, elliptic, rounded over the back; backs pubescent, sometimes glabrous or scabrous; margins pubescent or scabrous; the hairs similar to those on the lemma backs; tips obtuse; entire, awned; lemma awns (4)5– 8 mm; straight. |
Anthers | 0.5–1 mm. |
3–5 mm. |
2n | =14. |
=14. |
Bromus tectorum |
Bromus orcuttianus |
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Distribution | ||
Discussion | Disturbed areas, sagebrush steppe, degraded grasslands, roadsides. 0–2400 m. BR, BW, Casc, Col, CR, ECas, Lava, Owy, Sisk, WV. CA, ID, NV, WA; throughout North America; worldwide. Exotic. Bromus tectorum is a relatively short grass with drooping inflorescences. Similar B. sterilis and B. diandrus have longer glumes, lemmas, and awns, and spikelets that hang down at a shallower angle than those of B. tectorum. The introduction of B. tectorum to shrub steppe habitats during a time of massive overgrazing in the late 1800s has made restoration of native plant communities difficult or impossible, even where grazing no longer occurs. Fast-growing B. tectorum seedlings outcompete slower growing native grass seedlings for water in drying soils. At maturity, the awns make B. tectorum unpalatable to livestock. |
Dry montane conifer forests, especially ponderosa pine; chaparral, openings, sometimes in moister sites. 700–2200m. BW, Casc, ECas, Lava, Sisk. CA, WA; southeast to AZ. Native. Bromus orcuttianus is a grass of open, upland forests. The inflorescence of B. orcuttianus is upright and open with stiff, spreading branches. Bromus suksdorfii has a denser inflorescence, and B. laevipes has more flexuous branches and 5-veined upper glumes. Bromus orcuttianus is an uncommon native grass that seems to have declined in numbers, probably due to grazing. |
Source | Flora of Oregon, volume 1, page 374 Barbara Wilson, Richard Brainerd, Nick Otting |
Flora of Oregon, volume 1, page 372 Barbara Wilson, Richard Brainerd, Nick Otting |
Sibling taxa | ||
Synonyms | Bromus tectorum var. glabratus, Bromus tectorum var. nudus, Bromus tectorum var. tectorum | Bromus orcuttianus var. orcuttianus |
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