The grass genera of the world
Type species: Type: H. cylindrica (Willd.) Greuter.
Including Monerma (Willd.) Coss. & Dur.
Habit, vegetative morphology. Annual; caespitose. Culms 5–40(–47) cm high; herbaceous; branched above; 2–5 noded. Culm nodes exposed; glabrous. Culm internodes solid. Young shoots intravaginal. Leaves not basally aggregated; non-auriculate. Sheaths keeled or not, terete to inflated. Leaf blades linear; apically cucullate; narrow; 1.5–2.5 mm wide; flat, or rolled (convolute); without cross venation; persistent. Ligule an unfringed membrane; truncate; (0.2–)0.6–1 mm long.
Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant (with rudiments at the base of the spikelet), or all alike in sexuality; hermaphrodite, or hermaphrodite and sterile.
Inflorescence. Inflorescence a single spike (with a hard, cylindrical, articulated rachis, the spikelets embedded in alternate notches). Rachides hollowed (notched). Inflorescence espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes disarticulating; disarticulating at the joints. Spikelets solitary; not secund; distichous.
Female-fertile spikelets. Spikelets 4–8 mm long; adaxial (with reference to the missing G1); compressed dorsiventrally; falling with the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets, or naked. Hairy callus absent. Callus absent.
Glumes one per spikelet (in all but the two-glumed terminal spikelet, the leathery G2 alone is present and covers the hollow of the rachis); relatively large (firm); long relative to the adjacent lemmas; dorsiventral to the rachis; hairless; pointed (acuminate); awnless; non-carinate. Upper glume 3–7(–9) nerved (the nerves raised). Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets when present, distal to the female-fertile florets. The distal incomplete florets 1; merely underdeveloped (rudimentary).
Female-fertile florets 1. Lemmas lanceolate; less firm than the glumes (membranous); not becoming indurated; entire; pointed; awnless; hairless; non-carinate; 3(–5) nerved; with the nerves non-confluent (the laterals short). Palea present; relatively long; entire to apically notched; awnless, without apical setae; thinner than the lemma (hyaline); not indurated; 2-nerved; weakly 2-keeled. Palea keels wingless. Lodicules present; 2; free; membranous; glabrous; toothed, or not toothed. Stamens 1–3. Anthers 1.8–3.5 mm long; not penicillate. Ovary apically glabrous. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small to medium sized (3–4.3 mm long); oblong to ellipsoid; not grooved; compressed dorsiventrally to not noticeably compressed. Hilum short (ovate to elliptic, about 0.6 mm long). Embryo small; not waisted. Endosperm hard; with lipid; containing compound starch grains. Embryo with an epiblast.
First seedling leaf with a well-developed lamina. The lamina narrow; erect.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally (fairly thick walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs absent. Stomata common. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Costal short-cells predominantly paired. Costal silica bodies rounded and tall-and-narrow.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs, or nodular in section; with the ribs more or less constant in size. Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups (at the bases of the furrows); in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming figures. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 13. 2n = 26 and 52. 2 and 4 ploid. Chromosomes large.
Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Poeae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Parapholiinae. 1 species (H. cylindrica).
Distribution, phytogeography, ecology. Mediterranean to Iraq.
Commonly adventive. Mesophytic; species of open habitats. Meadows, etc., often coastal.
Rusts and smuts. Smuts from Ustilaginaceae. Ustilaginaceae Ustilago.
References, etc. Leaf anatomical: studied by us.
Illustrations. • H. cylindrica, as Monerma: P. Beauv. (1812). • H. cylindrica: Gardner, 1952. • General aspect and inflorescence (H. cylindrica): Gibbs Russell et al., 1990. • H. cylindrican TS 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: 11th December 2017. delta-intkey.com/grass’.