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Key to families | Table of families and genera

Specimen numbers are hyperlinked to records in the Consortium of California Herbaria data view where possible. Taxa are hyperlinked to entries in the Jepson Interchange via the "[Online Interchange]" link.

 

BROMUS BROME, CHESS

Jeffery M. Saarela & Paul M. Peterson


Annual to perennial herb. Leaf: basal and cauline; sheath closed to near top, hairy or glabrous; ligule <= 7 mm, membranous, entire to fringed; blade flat to inrolled. Inflorescence: generally raceme- or panicle-like, open to dense; pedicels generally stiff, rigid. Spikelet: strongly laterally compressed to cylindric; florets 3–30; axis breaking above glumes and between florets; glumes unequal, generally < lower floret, lower 1–3-veined, upper 3–7-veined, back rounded to strongly keeled, tip acute; lemma 5–9-veined, tip 2-toothed or entire, acute to obtuse, awned from between teeth or awns 0; palea generally < lemma.
± 160 species: temperate worldwide. (Greek: ancient name) [Pavlick and Anderton 2007 FNANM 24:193–237; Saarela et al. 2007 Aliso 23:450–467] Bromus scoparius L., Bromus erectus Huds. not known to be naturalized in California. Bromus pacificus Shear not in California.
Unabridged note: Report in FNANM of Bromus pacificus Shear (in HSC) based on misidentification.

Key to Bromus

1. Spikelet strongly flattened; lemma strongly keeled (sect. Ceratochloa)

2. Lemma awn 0–3.5 mm; lemma veins prominent ..... B. catharticus var. catharticus

2' Lemma awn 4–15 mm; lemma veins obscure or prominent

3. Some lower inflorescence branches > 10 cm, spreading to nodding ..... B. sitchensis

3' Lower inflorescence branches < 10 cm, or if longer, erect to ascending

4. Upper glume ± = lowermost lemma

5. Annual; lower glume 3–5-veined, upper 9–15 mm, 5–9-veined; lemma 7–veined, margin generally hairy (occasionally glabrous), backs hairy or glabrous, awn 7–15 mm; anthers <= 0.5 mm ..... B. arizonicus

5' Perennial herb; lower glume 5–7(9)-veined, upper 11–20 mm, 7–9-veined; lemma 9–11-veined, generally hairy at least distally, awn 6–12 mm; anthers 0.6–1 mm ..... B. catharticus var. elatus (2)

4' Upper glume generally < lowermost lemma — lemma scabrous or variously hairy, marginal hairs if present similar in length to those on back

6. Inflorescence dense, pedicel generally < spikelets; spikelets crowded, overlapping, stalks not visible; stem 20–80 cm, occasionally bent at base; stem, leaves glabrous or occasionally scabrous; ligule <= 6 mm ..... B. maritimus

6' Inflorescence loose to compact, at least some pedicels > spikelets; spikelets not crowded or overlapping, stalk often visible; stem 50–120 cm, erect; stem, leaves often hairy; ligule generally < 4 mm

7. Most awns >= (6)7 mm

8. Lemma generally uniformly hairy, occasionally scabrous, veins 7, obscure ..... B. carinatus var. carinatus

8' Lemma generally hairy at least distally, veins 9–11 on distal 1/2, prominent ..... B. catharticus var. elatus (2)

7' Most awns < 7 mm

9. Sheath throat and/or lemma hairy ..... B. carinatus var. marginatus

9' Sheath throat, lemma glabrous ..... B. polyanthus

1' Spikelet not strongly flattened; lemma rounded over midrib and not strongly keeled

10. Lemma tip conspicuously 2-toothed, teeth translucent, awn-like to acuminate, 1–7 mm; largest lemmas generally < 2 mm wide

11. Lemma awn bent and/or twisted (sect. Neobromus) ..... B. berteroanus

11' Lemma awn straight, not twisted (sect. Genea)

12. Lemma mostly > 20 mm; awn 30–65 mm ..... B. diandrus

12' Lemma mostly < 20 mm; awn 8–30 mm

13. Inflorescence dense, branches erect to ascending ..... B. madritensis

14. Inflorescence branches occasionally > spikelets, shortest branch on lowest inflorescence node 6–24 mm, longest branch on lowest node 0–1 × branched; sterile florets <= 3; inflorescence internodes gradually reduced upwards; florets not overlapping at maturity ..... subsp. madritensis

14' Inflorescence branches < spikelets, shortest branch on lowest inflorescence node <= 6 mm, longest branch on lowest node 2–5 × branched; sterile florets 3+; inflorescence internodes abruptly reduced upwards; florets overlapping at maturity ..... subsp. rubens

13' Inflorescence open, branches spreading to nodding

15. Spikelets 1(3) per inflorescence branch; inflorescence generally simple; branches > spikelets (< when inflorescence reduced to 1(3) spikelets); lemma 13–20 mm; awn 15–30 mm ..... B. sterilis

15' Spikelets 1–14 per inflorescence branch; inflorescence branched 1–5 ×; branches < or > spikelets; lemma 9–13 mm; awn 8–18 mm ..... B. tectorum

10' Lemma tip entire or inconspicuously 2-toothed, teeth generally not translucent, 0–3 mm; largest lemmas generally > 2 mm wide (except in Bromus vulgaris)

16. Annual; lower glume 3(5)-veined; upper glume 5–9-veined (sect. Bromus)

17. Lemma inflated, 6–8 mm wide; awn 0–1 mm; spikelet ovate ..... B. briziformis

17' Lemma not inflated, 1–5 mm wide; awn 2–20 mm; spikelet lanceolate to lance-ovate

18. Lemma papery, veins generally strongly raised; inflorescence generally ± dense

19. Awn from > 3 mm below lemma tip, bent; all pedicels << spikelets; inflorescence branches erect ..... B. caroli-henrici

19' Awn from < 1.5 mm below lemma tip, straight (curved); generally some pedicels > spikelets; inflorescence branches erect to spreading ..... B. hordeaceus

18' Lemma leathery, veins generally not strongly raised; inflorescence generally ± open

20. Lemma awn from 1.5–5 mm below tip

21. Lower glume 7–10 mm; upper glume 8–12 mm; inflorescence branches conspicuously S-curved ..... B. arenarius

21' Lower glume 4–7 mm; upper glume 5–9.5 mm; inflorescence branches ± wavy, sometimes S-curved

22. Inflorescence panicle-like, branches generally with > 1 spikelet; membranous lemma margin 0.3–0.6 mm wide ..... B. japonicus

22' Inflorescence generally raceme-like, branches generally with 1 spikelet; membranous lemma margin 0.6–0.9 mm wide ..... B. squarrosus

20' Lemma awn from < 1.5 mm below tip

23. Anthers 2.5–5 mm; spikelets lance-linear, narrowing only slightly towards tip; lower leaf sheaths with dense, softly appressed hairs; spikelets generally purple-tinged ..... [B. arvensis]

23' Anthers < 2.5(3) mm; spikelets lance-ovate, narrowing conspicuously towards tip; lower leaf sheaths glabrous or sparsely to densely stiff-hairy; spikelets not purple-tinged.

24. Lower leaf sheath glabrous or sparsely short-hairy; spikelet widening in fruit, stalk becoming tough, persistent, visible as lemma wraps around fruit; fruit U- and V-shaped in ×-section ..... B. secalinus

24' Lower leaf sheath long-hairy; spikelets not widening substantially in fruit, lemmas generally continuing to obscure stalks; fruit flat or C-shaped in ×-section

25. Inflorescence broad, spreading, some inflorescence branches > 4 cm, 1–3 spikelets per branch; lowest lemma awn generally < other awns; spikelets 15–30 mm; 2nd lowest lemma 7.5–11 mm, glabrous or hairy, margin often broadly angled; anthers 1.3–2.5 mm ..... B. commutatus

25' Inflorescence narrow, generally unbranched, inflorescence branches < 4 cm, 1 spikelet per branch; all awns ± equal; spikelet 11–18 mm; 2nd lowest lemma 7–9 mm, glabrous, margin often smoothly curved; anthers 1.5–3 mm ..... B. racemosus

16' Perennial herb, bases fibrous, rhizomes generally 0; lower glume 1(3)-veined; upper glume 3(5)-veined (sect. Bromopsis)

26. Plants from rhizomes; awn 0–3 mm ..... B. inermis

26' Rhizomes 0; awn 1.5–11 mm

27. Lower glume generally 3-veined

28. Upper glume 5-veined

29. Ligule (1.5)2–4 mm; glume glabrous; upper glume 7–11 mm; leaf blade, sheath glabrous ..... B. laevipes

29' Ligule 0.4–1(2) mm; glume scabrous or hairy; upper glume 6–9 mm; leaf blade, sheath hairy or glabrous ..... B. pseudolaevipes

28' Upper glume 3-veined

30. Lemma awn 1.5–3(4) mm; blade 2–5 mm wide; anthers 1.5–3.5(4) mm ..... B. porteri

30' Lemma awn 3–9 mm; blade 3–12 mm wide; anthers 3–7 mm

31. Leaf blade, basal sheath hairy; stem nodes 3–7; inflorescence branches generally spreading > 90° ..... B. grandis (2)

31' Leaf blade, basal sheath glabrous; stem nodes 2–3(4); inflorescence branches generally ascending to spreading <= 90° ..... B. orcuttianus (3)

27' Lower glume generally 1-veined

32. Glumes glabrous or minutely scabrous

33. Inflorescence narrow in flower, <= 2 cm wide; branches erect or tightly ascending ..... B. suksdorfii (2)

33' Inflorescence broader in flower, > 2 cm wide; branches erect, ascending, or nodding, generally ± widely spreading

34. Ligule (2)3–6(7) mm; lemma awn (4)6–11 mm ..... B. vulgaris (2)

34' Ligule 0.5–3 mm; lemma awn (2)3–7(9) mm

35. Lemma margin not densely hairy; lemma awn (4)5–7(9) mm; inflorescence branches generally ascending to spreading <= 90° ..... B. orcuttianus (3)

35' Lemma margin densely hairy; lemma awn (2)3–5(6.5) mm; inflorescence branches spreading to nodding > 90°

36. Lemma back glabrous or sparsely hairy with hairs to 0.1 mm; anthers(0.9)1–1.4(1.6) mm; upper glumes (6.2)7.1–8.5(9.5) mm; basal sheath glabrous or long-hairy; upper stem blade hairy on upper surface; upper stem sheath, nodes generally hairy; fruit (5.4)6.2–7.2(7.5) mm ..... B. ciliatus

36' Lemma back sparsely to densely hairy with hairs > 0.1 mm; anthers (1.2)1.6–2.7(3.4) mm; upper glumes (7.8)8.9–11.3(13.2) mm; basal sheath densely, ± short-hairy, upper stem sheath glabrous; upper stem blade upper surface glabrous; upper stem nodes generally glabrous; fruit (6.9)7.7–9.7(10.5) mm ..... B. richardsonii

32' Glumes hairy

37. Inflorescence narrow at flower, <= 2 cm wide, branches erect or tightly ascending; leaf blade, sheath glabrous ..... B. suksdorfii (2)

37' Inflorescence broader at flower, > 2 cm wide, branches erect, ascending, or nodding; leaf blade, sheath hairy or glabrous

38. Ligule (2)3–6(7) mm; lemma awn (4)6–11 mm; inflorescence branches glabrous or scabrous ..... B. vulgaris (2)

38' Ligule 1–3 mm; lemma awn 3–7(9) mm; inflorescence branches hairy

39. Lower sheath long-soft-hairy, hairs 2–4 mm, or glabrous; leaf blade glabrous ..... B. orcuttianus (3)

39' Lower sheath densely short-stiff-hairy, hairs <=1 mm; leaf blade hairy

40. Longest leaf blade (13)18–38 cm; nodes 3–7 per stem ..... B. grandis (2)

40' Longest leaf blade 7.5–16.5 cm; nodes 1–2(3) per stem ..... B. hallii

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