The grass genera of the world
The grass genera of the world | |
From the Greek opsis (appearance) and Micropyrum (a related grass genus), alluding to similarity.
Habit, vegetative morphology. Perennial. Culms 30–110 cm high; herbaceous; unbranched above; tuberous. Culm nodes glabrous. Leaves not basally aggregated. Sheath margins free. Leaf blades linear; narrow; 1–5 mm wide (10–25 cm long); without cross venation; persistent. Ligule an unfringed membrane.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence a single raceme (spikelike). Rachides hollowed (to receive the spikelets). Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; not secund; distichous (seemingly); subsessile to pedicellate (the pedicels about 0.5 mm long); not imbricate.
Female-fertile spikelets. Spikelets 10–26 mm long; adaxial; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; hairless; the rachilla extension with incomplete florets. Hairy callus absent. Callus short; blunt (glabrous).
Glumes two; very unequal; shorter than the spikelets; shorter than the adjacent lemmas; dorsiventral to the rachis; hairless; not subulate; awnless; similar. Lower glume 1 nerved. Upper glume 3 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped. Spikelets without proximal incomplete florets.
Female-fertile florets 3–13. Lemmas not becoming indurated; entire; pointed; awned. Awns 1; median; dorsal; from near the top; non-geniculate; hairless; much shorter than the body of the lemma to about as long as the body of the lemma (2–6 mm long, slender). Lemmas hairless; glabrous; non-carinate (dorsally rounded); 5 nerved. Palea present; relatively long; entire to apically notched; awnless, without apical setae; not indurated; 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; glabrous; toothed (bilobed). Stamens 3. Anthers 3 mm long. Ovary glabrous; without a conspicuous apical appendage. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit adhering to lemma and/or palea; small to medium sized (about 4 mm long).
Transverse section of leaf blade, physiology. Leaf blade with distinct, prominent adaxial ribs; with the ribs more or less constant in size. Midrib not readily distinguishable; with one bundle only. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Taxonomy. Pooideae; Poodae; Poeae.
Distribution, ecology, phytogeography. 1 species; Spain. In damp sands.
Holarctic. Tethyan. Mediterranean.
References, etc. Morphological/taxonomic: Zarco and Cabezudo 1983.
Special comments. Fruit data wanting. 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’.