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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.


Annual to perennial herb, cespitose, occasionally from short rhizomes. Stem: decumbent to erect, generally abruptly bent at base; nodes glabrous or pubescent. Leaf: sheath glabrous or hairy; ligules translucent; auricles present or 0; blade flat or ± rolled. Inflorescence: spike-like, dense; axis breaking apart at nodes at maturity (except in Hordeum vulgare); spikelets 2-ranked, strongly overlapping, 3 per node (central + 2 lateral). Central spikelet: bisexual, generally sessile; with 1 stalked or sessile floret; glumes awn-like, generally > floret; lemma awned. Lateral spikelet: sterile or staminate (bisexual in Hordeum vulgare), generally short-stalked; floret 1, sessile; glumes awn-like, > floret, lemma generally awned.
32 species: temperate worldwide except Australia. (Latin: ancient name for barley) [von Bothmer et al. 2007 FNANM 24:241–252] As treated here, including Critesion. Hybridizes with Elymus to produce ×Elyhordeum species. Source of edible grains, sugar, ornamental, and weeds; enzymes from sprouts used in beer-making. Lemma or floret measurements do not include awns. Hordeum pusillum Nutt. has been reported for Ventura and San Diego cos., but it does not appear to be naturalized.
Unabridged references: [Baum & Bailey 1990 Canad J Bot 68:2433–2442]

Key to Hordeum

1. Auricles of upper leaves well developed, 1–4(8) mm

2. Inflorescence axis generally remaining intact at maturity; lateral spikelets sessile (stalked in sterile plants); glume margins not ciliate ..... [H. vulgare]

2' Inflorescence axis breaking apart at maturity; lateral spikelets stalked; glume margins ciliate ..... H. murinum

3. Central spikelet stalk 0–0.5 mm; lemma of central floret generally = lemma of lateral floret; palea of lateral floret scabrous to glabrous ..... subsp. murinum

3' Central spikelet stalk 1–2 mm; lemma of central floret < lemma of lateral floret; palea of lateral floret hairy or scabrous on lower 1/2

4. Lemma of central floret <= those of lateral florets; palea of lateral florets long-hairy on lower 1/2; anthers of central florets < 1/2 those of lateral florets ..... subsp. glaucum

4' Lemma of central floret << those of lateral florets; palea of lateral florets scabrous on lower 1/2; anthers of central spikelets = those of lateral florets ..... subsp. leporinum

1' Auricles of upper leaves generally 0 (vestigial rudiments occasionally present on lower leaves)

5. Glumes strongly divergent at maturity

6. Glumes of central spikelet 11–28 mm, flat near base ..... H. arizonicum

6' Glumes of central spikelet (15)35–85 mm, bristle-like throughout ..... H. jubatum subsp. jubatum

5' Glumes generally straight with age (slightly spreading in some Hordeum brachyantherum)

7. Perennial herb; inflorescence fully exserted at maturity ..... H. brachyantherum

8. Leaf sheath generally glabrous, blade glabrous or sparsely short-hairy; stem generally robust ..... subsp. brachyantherum

8' Leaf sheath generally densely hairy, blade generally short- and long-hairy; stem slender ..... subsp. californicum

7' Annual; inflorescence generally ± enclosed in upper sheath at maturity (except Hordeum marinum subsp. gussoneanum)

9. Awn of lateral spikelet lemma 3–8 mm ..... H. marinum subsp. gussoneanum

9' Awn of lateral spikelet lemma 0–1.2 mm

10. Nodes glabrous; glumes of central spikelet rounded to slightly flattened near base ..... H. depressum

10' Nodes generally pubescent; glumes of central spikelet distinctly flattened at base ..... H. intercedens


Citation for the whole project: Jepson Flora Project (eds.) [year] Jepson eFlora, [accessed on month, day, year]
Citation for an individual treatment: [Author of taxon treatment] [year]. [Taxon name] in Jepson Flora Project (eds.) Jepson eFlora, [URL for treatment]. Accessed on [month, day, year].
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