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Hordeum jubatum

©Timothy M. Jones

Hordeum vulgare

©University of Tennessee Herbarium, Knoxville

Vegetative Morphology

 
Plants summer or winter annuals, or perennials; cespitose, sometimes shortly rhizomatous.
Culms to 135(150) cm, erect, geniculate, or decumbent.
Nodes glabrous or pubescent.
Sheaths open, pubescent or glabrous.
Auricles present or absent.
Ligules hyaline, truncate, erose.
Blades flat to more or less involute, more or less pubescent on both sides.

Reproductive Morphology

 
Inflorescences usually spikelike racemes, sometimes spikes, all customarily called spikes, with 3 spikelets at each node.
Central spikelets usually sessile, sometimes pedicellate, pedicels to 2 mm.
Lateral spikelets usually pedicellate, pedicels curved or straight, sometimes all 3 spikelets sessile in cultivated plants.
Disarticulation usually in the rachises, the spikelets falling in triplets, cultivated forms generally not disarticulating.
Spikelets with 1 floret.
Glumes awnlike, usually exceeding the floret.
Lateral spikelets usually sterile or staminate, often bisexual in cultivated forms.
Florets pedicellate, usually reduced.
Lemmas awned or unawned.
Central spikelets bisexual.
Florets sessile.
Rachillas prolonged beyond the floret.
Lemmas ovate, glabrous to pubescent, 5-veined, usually awned, rarely unawned.
Paleas almost equal to the lemmas, narrowly ovate, keeled.
Lodicules 2, broadly lanceolate, margins ciliate.
Anthers 3, usually yellowish.
Caryopses usually tightly enclosed in the lemma and palea at maturity.

Species Distribution Maps

Hordeum intercedens Hordeum jubatum Hordeum arizonicum
Hordeum pusillum Hordeum marinum Hordeum bulbosum
Hordeum depressum Hordeum secalinum Hordeum vulgare
Hordeum brachyantherum Hordeum murinum  

Chromosome Number(s)

2n = 14, 28, 42

Additional Notes

Name from the old Latin name for barley.

Hordeum is a genus of 32 species that grow in temperate and adjacent subtropical areas, at elevations from 0-4500 m. The genus is native to Eurasia, the Americas, and Africa, and has been introduced to Australasia. The species are confined to rather moist habitats, even on saline soils. The annual species occupy seasonally moist habitats that cannot sustain a continuous grass cover.

Some species of Hordeum, such as H. marinum and H. murinum, are cosmopolitan weeds. Hordeum vulgare is widely cultivated for feed, malt, and flour. Archeological records suggest that Hordeum and Triticum were two of the earliest domesticated crops.

Eleven species of Hordeum grow in the Flora region: six are native, three are established weeds, and two are cultivated and occasionally persist as weeds. Hordeum secalinum has been reported from the Flora region, but the reports are based on misidentifications.

Four different haplomes are present in Hordeum. Hordeum vulgare and H. bulbosum have the I genome (often called the H genome by plant breeders), North American diploid species are based on the H genome, diploid H. marinum on the X genome, and diploids in the H. murinum group on the Y genome.

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Name/Synonymy Publication Info

Hordeum L., Sp. pl. 1:84 (1753). LEC: Hordeum vulgare L. [Bowden, Canad. J. Bot. 37:679 (1959)].

Zeocriton Wolf, Gen. pl. 21 (1776). TYPE: Zeocriton commune P. Beauv. [=Hordeum vulgare L.].

Critesion Raf., J. Phys. Chim. Hist. Nat. Arts 89:103 (1819). TYPE: Critesion geniculatum Raf., nom. illeg. [=Hordeum jubatum L.].

Critho E. Meyer, Index Seminum Regiomont [Königsberg] 5 (1848). TYPE: Critho aegiceras (Royle) E. Meyer [=Hordeum vulgare subsp. vulgare var. coeleste L.].

Treatment from

R. von Bothmer, C. Baden, and N.H. Jacobsen. Hordeum in Flora of North America, volume 24. In prep. Oxford University Press.

Fact Sheet Developed By

Pedro Oñativia Lake © 2006.