Family: Poaceae |
Roland von Bothmer, Claus Baden, Niels H. Jacobsen (2007) FNA 24:241-252 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; auriclespresent or absent; ligules hyaline, truncate, erose; blades flat to more or less involute, more or less pubescent on both sides. 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; disarticulationusually 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. 2n = 14, 28, 42. Name from the old Latin name for barley. Hordeum includes 33 species that grow in temperate and adjacent subtropical areas at 0-4500 m. It is native to Eurasia, Africa, and the America. Spike measurements and lemma lengths do not include the awns unless otherwise stated. ©Utah State University; reproduced with permission. Keys are available for: the world, North America north of Mexico, and Pakistan.
Blattner (2009) proposed a new infrageneric treatment of Hordeum and also changed the customary designation of the haplomes present in the genus. His usage is reflected in Brassac and Blattner (2015) which presents the species-level phylogeny and polyploid relationships in Hordeum, and on this web site. T there are four haplomes (sets of chromosomes) in Hordeum. The most widespread haplome is what Blattner calls the I haplome.This haplome was previously referred to by systematists, but not recent plant breeders, as the H haplome. Blattner uses H for the haplome found in the cultivated barleys, the usage of plant breeders. It was not until ??, that different names were given to the haplome associated with wild barleys. Systematists preferred to use H for the haplome found in the majority of Hordeum species. Most existing references to the H haplome refer to what Blattner calls the I haplome. The other two haplomes are, Xa, found in Hordeum marinum and Hordeum geniculatum,and Xu, found in Hordeum murinum. Brassac and Blattner (2015) recognized three alloploid species within Hordeum. All three combine the I and Xa haplomes. The I haplome is also one of the haplomes in species of Elymus, Roegneria, Campeiostachys, and Stenostachys. |