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The grass genera of the world

L. Watson, T.D. Macfarlane, and M.J. Dallwitz

Cynosurus L.

From the Greek kynos, of a dog and oura, tail, referring to the shape of the panicle.

Dog’s tail grasses.

Type species: Type: C. cristatus L.

Including Falonia Adans.

Habit, vegetative morphology. Annual, or perennial; caespitose. Culms 10–90 cm high; herbaceous; unbranched above; 3–10 noded. Culm nodes exposed; glabrous. Culm internodes hollow. Leaves not basally aggregated; non-auriculate. Sheath margins free. Sheaths not keeled, terete. Leaf blades linear; apically flat; broad, or narrow; 0.5–9(–14) mm wide; flat; without cross venation; persistent; once-folded in bud. Ligule an unfringed membrane; truncate, or not truncate; 0.5–8.5 mm long.

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; hermaphrodite and sterile; overtly heteromorphic (fertile spikelets mixed with and more or less concealed by sterile ones consisting of rigid, lanceolate, awned glumes and lemmas). Plants outbreeding.

Inflorescence. Inflorescence paniculate; contracted; spicate, or more or less irregular. Primary inflorescence branches borne biseriately on one side of the main axis. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets secund; shortly pedicellate, or subsessile.

Female-sterile spikelets. The sterile spikelets consisting of rigid, lanceolate, awned glumes and lemmas occurring among the fertile ones.

Female-fertile spikelets. Spikelets 2.8–10 mm long; compressed laterally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; hairless. Hairy callus absent. Callus short; blunt.

Glumes two; more or less equal; shorter than the adjacent lemmas, or long relative to the adjacent lemmas; awnless; carinate; similar (narrow, thin). Lower glume 1(–2) nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets distal to the female-fertile florets.

Female-fertile florets (1–)2–5. Lemmas similar in texture to the glumes to decidedly firmer than the glumes (papery or leathery); not becoming indurated; entire, or incised; awned. Awns 1; median; from a sinus, or apical; from near the top; non-geniculate; much shorter than the body of the lemma to much longer than the body of the lemma; entered by one vein. Lemmas hairy, or hairless; non-carinate; 5 nerved. Palea present; relatively long; tightly clasped by the lemma; apically notched (shortly bifid); thinner than the lemma (membranous); 2-nerved; 2-keeled. Palea keels wingless. Lodicules present; 2; free; membranous; glabrous; toothed. Stamens 3. Anthers 0.7–3.5 mm long; not penicillate. Ovary apically glabrous. Styles free to their bases. Stigmas 2; white.

Fruit, embryo and seedling. Fruit adhering to lemma and/or palea (to the palea); small to medium sized (2.2–4.3 mm long); ovoid or ellipsoid; longitudinally grooved, or not grooved; compressed dorsiventrally to not noticeably compressed. Hilum short, or long-linear (elliptic or linear). Embryo small; not waisted. Endosperm hard; with lipid, or without lipid; containing compound starch grains. Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.

Seedling with a long mesocotyl; with a tight coleoptile. First seedling leaf with a well-developed lamina. The lamina narrow; 1 veined.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally (the intercostals very large); differing markedly in wall thickness costally and intercostally (the costals thicker-walled, pitted). Mid-intercostal long-cells fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata absent or very rare (C. cristatus), or common (C. echinatus); in C. echinatus (42–)45–50(–51) microns long. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells absent or very rare; not paired (solitary); not silicified. Costal short-cells predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous, or horizontally-elongated smooth, or rounded.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade with distinct, prominent adaxial ribs, or ‘nodular’ in section, or adaxially flat; with the ribs more or less constant in size, or with the ribs very irregular in sizes. Midrib conspicuous, or not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups (in the furrows); in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; nowhere forming ‘figures’. Sclerenchyma all associated with vascular bundles.

Culm anatomy. Culm internode bundles in one or two rings.

Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid. Chromosomes ‘large’.

Classification. Watson & Dallwitz (1994): Pooideae; Poodae; Poeae. Soreng et al. (2015): Pooideae; Poodae; Poeae; Cynosurinae. 8 species.

Distribution, phytogeography, ecology. Europe, western Asia, North and South Africa.

Commonly adventive. Mesophytic, or xerophytic; species of open habitats. Meadows, disturbed ground.

Economic aspects. Significant weed species: C. cristatus, C. echinatus. Cultivated fodder: C. cristatus. Lawns and/or playing fields: C. cristatus.

Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia graminis, Puccinia coronata, and ‘Uromycesdactylidis. Smuts from Tilletiaceae and from Ustilaginaceae. Tilletiaceae — Entyloma and Tilletia. Ustilaginaceae — Ustilago.

References, etc. Leaf anatomical: Metcalfe 1960; studied bu us - C. cristatus L., C. echinatus L.

Illustrations. • C. cristatus, general aspect: Eng. Bot. (1872). • C. cristatus, general aspect: J. Curtis, 1824. • C. echinatus, general aspect: Eng. Bot. (1872). • C. echinatus: Gibbs Russell et al., 1990. • C. echinatus, inflorescence, spikelets, floret. • C. echinatus, 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: 11th December 2017.’.