The grass genera of the world
The grass genera of the world |
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From the Greek krithe (barley) and opsis (appearance), from fancied resemblance of inflorescence.
Habit, vegetative morphology. Annual; caespitose. Culms 15–30 cm high; herbaceous; unbranched above. Culm nodes glabrous. Leaves not basally aggregated; auriculate. Leaf blades linear (acuminate); narrow; to 3 mm wide; flat; without cross venation; persistent. Ligule an unfringed membrane.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality.
Inflorescence. Inflorescence a false spike, with spikelets on contracted axes (the clusters each reduced to two spikelets). Rachides flattened. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes disarticulating; disarticulating at the joints. Spikelets paired; not secund; the pairs alternately distichous.
Female-fertile spikelets. Spikelets about 15 mm long; compressed laterally; falling with the glumes (and with the joint). Rachilla prolonged beyond the uppermost female-fertile floret; hairy; the rachilla extension with incomplete florets.
Glumes two; more or less equal; long relative to the adjacent lemmas; subulate; awned; non-carinate; similar (leathery, narrow, awn-like above). Lower glume 3 nerved. Upper glume 3 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets 1; merely underdeveloped. Spikelets without proximal incomplete florets.
Female-fertile florets 1. Lemmas attenuate into the awn; similar in texture to the glumes (and similar to them in form); not becoming indurated; entire; pointed; awned. Awns 1; median; apical; non-geniculate; hairless (scabrid); about as long as the body of the lemma to much longer than the body of the lemma (4–7 mm long, erect); entered by several veins. Lemmas hairy, or hairless; non-carinate; 5 nerved. Palea present; relatively long; awnless, without apical setae; 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; ciliate; toothed, or not toothed. Stamens 3. Anthers not penicillate. Ovary hairy. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit adhering to lemma and/or palea; medium sized; longitudinally grooved; compressed dorsiventrally; with hairs confined to a terminal tuft. Hilum long-linear. Embryo small.
Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid. Haplomic genome content K.
Taxonomy. Pooideae; Triticodae; Triticeae.
Distribution, ecology, phytogeography. 1 species; North Africa & the Orient. Xerophytic; species of open habitats. In dry grassland.
Holarctic and Paleotropical. Tethyan. African. Mediterranean. Saharo-Sindian.
References, etc. Morphological/taxonomic: Löve 1984.
Special comments. Anatomical data wanting.
This description is offered for casual browsing only. We strongly advise against extracting comparative information from it. This is much more easily achieved using the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting specified attributes, summaries of attributes within groups of taxa, geographical distribution, classification, and species sampled for anatomy.
Cite this publication as: ‘Watson, L., and Dallwitz, M.J. 1992 onwards. The grass genera of the world: descriptions, illustrations, identification, and information retrieval; including synonyms, morphology, anatomy, physiology, phytochemistry, cytology, classification, pathogens, world and local distribution, and references. Version: 11th February 2012. http://delta-intkey.com’.