Ctenopsis De Not
From the Greek ktenos (a combe) and opsis (appearance), alluding to a comblike inflorescence.
Sometimes referred to Vulpia
Habit, vegetative morphology. Annual; caespitose. Culms 10–40 cm high; herbaceous. Culm nodes glabrous. Culm internodes hollow. Leaves not basally aggregated; non-auriculate. Leaf blades linear; narrow; setaceous; rolled (convolute); without cross venation; persistent; an unfringed membrane; 0.7–1 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence a single raceme, or paniculate (sometimes sparingly branched); contracted; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; secund (pectinate); pedicellate.
Female-fertile spikelets. Spikelets 3.5–12 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; hairless. Hairy callus absent.
Glumes two; very unequal; (the longer) long relative to the adjacent lemmas; dorsiventral to the rachis; pointed; awnless; non-carinate (rounded on the back); very dissimilar (the lower minute). Lower glume 0 nerved. Upper glume 3 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 3–14. Lemmas acuminate; less firm than the glumes (papery, the margins hyaline); not becoming indurated; entire; pointed; awnless, or mucronate (?); hairless; non-carinate; 5 nerved. Palea present; relatively long; apically notched; awnless, without apical setae; 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; glabrous; toothed. Stamens 3. Anthers 0.5–2.5 mm long; not penicillate. Ovary glabrous. Styles free to their bases. Stigmas 2; white.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small; longitudinally grooved; compressed dorsiventrally. Hilum short. Embryo small; not waisted.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous to lacking. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs absent. Stomata absent or very rare. Intercostal short-cells common; in cork/silica-cell pairs (mostly - some solitary); silicified (rarely), or 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; without adaxial palisade. Midrib conspicuous; with one bundle only. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (C. pectinella), or absent (C. patens); in C. pectinella forming ‘figures’ (having tall, narrow I’s with most bundles). Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid.
Taxonomy. Pooideae; Poodae; Poeae.
Distribution, ecology, phytogeography. 4 species; Mediterranean & western Asia. Species of open habitats.
Holarctic, Paleotropical, and Cape. Tethyan. African. Mediterranean. Saharo-Sindian and Sudano-Angolan. South Tropical African.
References, etc. Leaf anatomical: this project.
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).