The grass genera of the world
Type species: Type: E. ovatus (G.Forst.) P.Beauv.
Including Hystericina Steud.
Habit, vegetative morphology. Perennial; rhizomatous, or caespitose. Culms herbaceous; unbranched above. Culm nodes glabrous. Culm internodes solid, or hollow. Leaves not basally aggregated; non-auriculate. Leaf blades apically cucullate; narrow; not pseudopetiolate; without cross venation; persistent. Ligule an unfringed membrane; truncate; 1.5–3 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; contracted; capitate, or more or less ovoid. Primary inflorescence branches borne distichously. Inflorescence espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 2.5–10 mm long; compressed laterally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension naked. Hairy callus present.
Glumes two; relatively large; more or less equal; long relative to the adjacent lemmas; pointed (acute to acuminate); awnless; carinate (the keels stiffly ciliate); similar (membranous). Lower glume 1 nerved. Upper glume 1 nerved, or 3 nerved. Spikelets with female-fertile florets only.
Female-fertile florets 1. Lemmas decidedly firmer than the glumes (thinly leathery); not becoming indurated; incised; 2 lobed (the apex narrow, with two slender, erect, acuminate or setiform lateral lobes); mucronate (E. phleoides), or awned. Awns 1; median; from a sinus (or slightly behind it); non-geniculate; hairless (scabrid); entered by one vein. Lemmas hairless; non-carinate; distinctly 5–7(–11) nerved. Palea present; relatively long; minutely apically notched (3-toothed); 2-nerved; 2-keeled, or keel-less. Lodicules present; 2; free; membranous; ciliate; not toothed. Stamens 3. Anthers not penicillate. Ovary apically glabrous, or apically hairy. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small; longitudinally grooved; not noticeably compressed; glabrous, or hairy; with hairs confined to a terminal tuft. Hilum long-linear. Embryo small; not waisted. Endosperm liquid in the mature fruit, or hard; containing compound starch grains. Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.
Seedling with a short mesocotyl. First seedling leaf with a well-developed lamina. The lamina narrow; erect; 3–5 veined.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally (elongated); of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular to fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata common. Subsidiaries parallel-sided, or dome-shaped. Guard-cells overlapped by the interstomatals. Intercostal short-cells common (mainly adjacent to the costal regions), or absent or very rare; in cork/silica-cell pairs (usually), or not paired (sometimes solitary); silicified (when paired), or not silicified. Costal short-cells conspicuously in long rows, or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous, or horizontally-elongated smooth (a few, rectangular), or tall-and-narrow.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; nowhere forming figures. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 7. 2n = 42.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Aveneae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Agrostidinae. 7 species.
Distribution, phytogeography, ecology. Australia, New Zealand, New Guinea.
Mesophytic; glycophytic. In open woodland.
Rusts and smuts. Rusts Puccinia. Taxonomically wide-ranging species: Puccinia graminis.
References, etc. Morphological/taxonomic: Hubbard 1935. Leaf anatomical: this project.
Illustrations. • E. ovatus: Gardner, 1952. • Ligule of E. caespitosus. • E. cheelii, abaxial epidermis of leaf blade: this project. • E. cheelii, abaxial epidermis of leaf blade: this project
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’.