OregonFlora: Bromus catharticus vs. Bromus diandrus

	Bromus catharticus	Bromus diandrus
	rescue grass	ripgut brome
Habit		Plants annual, 20–90 cm tall.
Culms		puberulent.
Leaves		sheaths softly pilose, often with retrorse or spreading hairs; blades 3.5–27 cm × 1–9 mm, pilose on both surfaces.
Inflorescences		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		25–70 mm, moderately laterally compressed, with 4–11 florets.
Glumes		smooth or scabrous; lower glumes 15– 25 mm, 1–3-veined; upper glumes 25–35 mm, 3–5-veined.
Lemmas		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.
2n		=28, 42, 56.

	Bromus catharticus	Bromus diandrus
Distribution	[WildflowerSearch map] [BONAP county map]	[WildflowerSearch map] [BONAP county map]
Discussion	[Species with one variety or subspecies in Oregon.]	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	Flora of Oregon, volume 1, page 370 Barbara Wilson, Richard Brainerd, Nick Otting
Sibling taxa	B. arenarius, B. briziformis, 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. tectorum, 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
Subordinate taxa	B. catharticus var. catharticus
Synonyms	Bromus unioloides	Bromus rigidus, Bromus rigidus var. gussonei, Bromus rigidus var. rigidus
Web links	Local floras: CA, OR Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search	Local floras: CA, OR, WA Local Web sites: CalFlora, CalPhotos, Flora NW, PNW Herbaria WildflowerSearch iNaturalist (observations) USDA Plants Database LBJ Wildflower Center SEINet Plants of the World Online Encyclopedia of Life Wikipedia Google Image Search

Bromus diandrus

rescue grass

ripgut brome

Habit

Plants annual, 20–90 cm tall.

Culms

puberulent.

Leaves

sheaths softly pilose, often with retrorse or spreading hairs;

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

Inflorescences

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

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

Glumes

smooth or scabrous;

lower glumes 15– 25 mm, 1–3-veined;

upper glumes 25–35 mm, 3–5-veined.

Lemmas

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.

=28, 42, 56.

Bromus diandrus

Distribution

[WildflowerSearch map]

[BONAP county map]

[WildflowerSearch map]

[BONAP county map]

Discussion

[Species with one variety or subspecies in Oregon.]

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

Flora of Oregon, volume 1, page 370
Barbara Wilson, Richard Brainerd, Nick Otting

Sibling taxa