The grass genera of the world
Habit, vegetative morphology. Annual. Culms 10–40 cm high; herbaceous. Leaves non-auriculate. Leaf blades linear; narrow (?); without cross venation. Ligule an unfringed membrane; truncate; 2–4 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate (2–10 cm long, with up to 4 branches at each node); open (the branches and pedicels pulvinate); without conspicuously divaricate branchlets (by contrast with Cutandia); espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes disarticulating; falling entire (branches disarticulating at the pulvini). Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 8–25(–40) mm long; compressed laterally; disarticulating above the glumes and falling with the glumes; disarticulating between the florets (each lemma falling with the internode below, rather than the one above). Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets. Hairy callus absent.
Glumes two; very unequal; shorter than the adjacent lemmas; dorsiventral to the rachis; hairless (scabrid on the midribs); pointed (acuminate); shortly awned; non-carinate; similar. Lower glume 1 nerved. Upper glume 1–3 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets.
Female-fertile florets 5–12(–18). Lemmas aculeolate, acuminate; similar in texture to the glumes; not becoming indurated (firm); entire; pointed; awned (the awn to 8 mm long). Awns 1; median; from a sinus, or apical; non-geniculate; much shorter than the body of the lemma to about as long as the body of the lemma; entered by one vein. Lemmas hairless; non-carinate; without a germination flap; 3 nerved. Palea present; relatively long; 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; glabrous; toothed, or not toothed; not or scarcely vascularized. Stamens 3. Ovary apically glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit adhering to lemma and/or palea (to the palea); small (3 mm long); longitudinally grooved; compressed dorsiventrally. Hilum short (oblong-linear). Embryo small. Endosperm hard; containing compound starch grains.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells markedly different in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata common. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells absent or very rare. Costal zones with short-cells. Costal short-cells conspicuously in long rows (mainly, sometimes paired). Costal silica bodies horizontally-elongated crenate/sinuous, or horizontally-elongated smooth (few); not sharp-pointed.
Transverse section of leaf blade, physiology. C3. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs; with the ribs more or less constant in size. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 7.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Poeae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Parapholiinae. 1 species (V. stipoides).
Distribution, phytogeography, ecology. Mediterranean.
Xerophytic; species of open habitats. Dry sandy places.
References, etc. Leaf anatomical: this project.
Illustrations. • V. stipoides, as Vulpia incrassata: Coste, Fl. de France (1906)
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or 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 or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., Macfarlane, T.D., 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: 13th November 2017. delta-intkey.com/grass’.