OregonFlora species comparison

The green links below add additional plants to the comparison table. Blue links lead to other Web sites.
enable glossary links

Bromus tectorum

Bromus diandrus

cheatgrass, downy brome, downy chess

ripgut brome
Habit Plants annual, 5–90 cm tall. Plants annual, 20–90 cm tall.
Culms

puberulent.

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 softly pilose, often with retrorse or spreading hairs;

blades 3.5–27 cm × 1–9 mm, pilose on both surfaces.
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.

panicles 13–25 × 2–17 cm, nodding at maturity but occasionally erect;

branches 1–7 cm, stiffly erect to ascending or spreading, 1–2 spikelets.
Spikelets

10–20 mm, moderately laterally compressed, not densely crowded, 4–8 florets.

25–70 mm, moderately laterally compressed, with 4–11 florets.
Glumes

villous, pubescent, or glabrous;

lower glumes 4–9 mm, 1-veined;

upper glumes 7–13 mm, 3–5-veined.

smooth or scabrous;

lower glumes 15– 25 mm, 1–3-veined;

upper glumes 25–35 mm, 3–5-veined.
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.

22–30 mm, linear-lanceolate, scabrous, 7-veined;

margins hyaline;

tips acuminate; bifid;

teeth 3–5 mm, awned;

lemma awns 30–65 mm; straight.
Anthers

0.5–1 mm.

0.5–1 mm.
2n

=14.

=28, 42, 56.

Bromus tectorum

Bromus diandrus
Distribution
[WildflowerSearch map]
[BONAP county map]
[WildflowerSearch map]
[BONAP county map]
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.

Disturbed open areas, degraded grasslands. 0–1300m. Col, CR, ECas, Est, Lava, Sisk, WV. CA, ID, NV, WA; north to British Columbia, southeast to TX, south to Mexico, scattered in the eastern US; Europe. Exotic.

Bromus diandrus is a common weed, typically with gracefully curved inflorescences and long lemma awns. The long awns can lodge in the mouths and digestive tracts of herbivores, causing injury. Similar B. sterilis is smaller in all its parts.
Source Flora of Oregon, volume 1, page 374
Barbara Wilson, Richard Brainerd, Nick Otting		 Flora of Oregon, volume 1, page 370
Barbara Wilson, Richard Brainerd, Nick Otting
Sibling taxa
B. arenarius, B. briziformis, B. catharticus, B. ciliatus, B. commutatus, B. diandrus, B. hordeaceus, B. inermis, B. japonicus, B. laevipes, B. madritensis, B. orcuttianus, B. pacificus, B. rubens, B. secalinus, B. sitchensis, B. squarrosus, B. sterilis, B. suksdorfii, B. vulgaris
B. arenarius, B. briziformis, B. catharticus, B. ciliatus, B. commutatus, B. hordeaceus, B. inermis, B. japonicus, B. laevipes, B. madritensis, B. orcuttianus, B. pacificus, B. rubens, B. secalinus, B. sitchensis, B. squarrosus, B. sterilis, B. suksdorfii, B. tectorum, B. vulgaris
Synonyms Bromus tectorum var. glabratus, Bromus tectorum var. nudus, Bromus tectorum var. tectorum Bromus rigidus, Bromus rigidus var. gussonei, Bromus rigidus var. rigidus
Web links 
Unless otherwise noted, all data comes from OregonFlora.



Type/paste one or more Latin names into the boxes above; matching taxa will show up below the box as you type. You can use the up/down arrow keys to move through the list.

(If the plant you're looking for doesn't show up in the auto-complete list, that means it either isn't described in OregonFlora yet, or it's listed under a synonym.)

Choose a data source: Flora of North America, OregonFlora, UW Burke Herbarium

The species comparison tool is brought to you by:
Northwest Wildflowers