Grass Genera of the World

L. Watson and M. J. Dallwitz


Cynosurus L.

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

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; broad, or narrow; 0.5–9(–14) mm wide; flat; without cross venation; persistent; once-folded in bud; an unfringed membrane; truncate, or not truncate; 0.5–8.5 mm long.

Reproductive organization. Plants bisexual, 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. Spikelets without proximal incomplete 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 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’.

Taxonomy. Pooideae; Poodae; Poeae. Dog’s tail grasses.

Distribution, ecology, phytogeography. 8 species; Europe, western Asia, North and South Africa. Commonly adventive. Mesophytic, or xerophytic; species of open habitats. Meadows, disturbed ground.

Holarctic, Paleotropical, and Neotropical. Boreal and Tethyan. African. Euro-Siberian and Atlantic North American. Macaronesian, Mediterranean, and Irano-Turanian. Saharo-Sindian. Caribbean. European. Canadian-Appalachian.

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.

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

References, etc. Leaf anatomical: Metcalfe 1960; this project.

Illustrations. • General aspect. • Inflorescence, spikelets and floret. • Abaxial epidermis of leaf blade. Cynosurus echinatus.


Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘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.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).

Index