The grass genera of the world
Including Anachortus Jir sek and Chrtek
Habit, vegetative morphology. Annual, or perennial; caespitose. Culms 10–60 cm high; herbaceous; unbranched above. Culm nodes glabrous. Culm internodes hollow. Leaves non-auriculate. Leaf blades linear; narrow; 0.3 to 0.8 mm in diameter; setaceous, or not setaceous; folded, or rolled and acicular; without cross venation; persistent. Ligule an unfringed membrane; not truncate; 2–4 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; open, or contracted; with capillary branchlets, or without capillary branchlets; espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets 3–5 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; hairy; the rachilla extension naked. Hairy callus present. Callus short.
Glumes two; more or less equal; about equalling the spikelets; long relative to the adjacent lemmas; pointed; awnless; carinate; similar (lanceolate). Lower glume 1 nerved. Upper glume 1 nerved, or 3 nerved (at base). Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 2. Lemmas similar in texture to the glumes (thinly membranous); not becoming indurated; incised; shortly 2 lobed; not deeply cleft (minutely bidenticulate); awned. Awns 1; median; dorsal; from well down the back; geniculate (and peculiar, with a clavate apex enclosed by the glumes, and with a ring of minute hairs distal to the twisted lower half); much longer than the body of the lemma; entered by one vein. Lemmas hairless; non-carinate; 1 nerved. Palea present; relatively long; tightly clasped by the lemma; apically notched; awnless, without apical setae; 2-nerved. Lodicules present; 2; free; membranous; glabrous; toothed. Stamens 3. Anthers 0.5–1.5 mm long, or 0.4–0.5 mm long; not penicillate. Ovary apically glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit usually, slightly adhering to lemma and/or palea; small; longitudinally grooved; compressed dorsiventrally. Hilum short. Embryo small; not waisted. Endosperm liquid in the mature fruit, or hard; with lipid.
Seedling with a short mesocotyl; with a loose coleoptile, or with a tight coleoptile. First seedling leaf with a well-developed lamina. The lamina narrow; erect; 3 veined.
Abaxial leaf blade epidermis. Costal/intercostal zonation lacking. Papillae absent. Microhairs absent. Stomata absent or very rare. Intercostal short-cells common; in cork/silica-cell pairs and not paired; silicified (when paired). Prickles abundant. Costal short-cells predominantly paired. Costal silica bodies rounded, tall-and-narrow, and crescentic.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs (small, in the adaxial groove). Midrib not readily distinguishable (except by its position); with one bundle only. Bulliforms not present in discrete, regular adaxial groups. Combined sclerenchyma girders absent. Sclerenchyma not all bundle-associated. The extra sclerenchyma in a continuous abaxial layer.
Special diagnostic feature. Lemmas awned, the awn bearing a ring of minute hairs at the middle, and apically clavate.
Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid. Chromosomes large. Haploid nuclear DNA content 1.2 pg (1 species). Mean diploid 2c DNA value 2.3 pg.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Aveneae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Airinae. 5 species.
Distribution, phytogeography, ecology. Europe, Mediterranean.
Commonly adventive. Xerophytic; species of open habitats. In sandy places, often coastal.
Rusts and smuts. Rusts Puccinia. Taxonomically wide-ranging species: Puccinia graminis.
References, etc. Leaf anatomical: this project.
Illustrations. • C. canescens: P. Beauv. (1812). • C. canescens, general aspect: Eng. Bot. (1872). • Spikelets (C. canescens). • C. canescens, T.S. 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’.