Chaetopogon Janchen
Including Chaeturus Link
Habit, vegetative morphology. Annual. Culms 3–30 cm high; herbaceous. Leaves non-auriculate. Leaf blades linear; narrow; 0.5–1.5 mm wide; setaceous, or not setaceous; without cross venation; an unfringed membrane; not truncate (acute); 3–5 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; contracted (narrow); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; shortly pedicellate.
Female-fertile spikelets. Spikelets 2.8–3 mm long; compressed laterally; falling with the glumes (and with the short pedicel). Rachilla terminated by a female-fertile floret. Hairy callus absent.
Glumes two; very unequal to more or less equal; exceeding the spikelets; long relative to the adjacent lemmas; hairless; scabrous; (the lower only) awned; carinate, or non-carinate; very dissimilar (linear lanceolate, membranous, the lower produced into a long slender awn, the upper awnless). Lower glume 1–3 nerved. Upper glume 1–3 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas less firm than the glumes to similar in texture to the glumes (hyaline); not becoming indurated; entire, or incised; pointed; not deeply cleft; awned. Awns 1; median; from a sinus, or apical; non-geniculate; much shorter than the body of the lemma to about as long as the body of the lemma (?); entered by one vein. Lemmas hairless; non-carinate; without a germination flap; 1 nerved, or 3 nerved. Palea present; conspicuous but relatively short (about half as long as the lemma); apically notched (denticulate); awnless, without apical setae; not indurated (hyaline); 1-nerved, or nerveless; keel-less. Lodicules present; 2; free; membranous; glabrous; not toothed; not or scarcely vascularized. Stamens 3. Ovary glabrous. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit small (about 2 mm long); compressed dorsiventrally. Hilum short. Embryo small. Endosperm hard; with lipid; containing compound starch grains.
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. Mid-intercostal long-cells rectangular and fusiform; having straight or only gently undulating walls. Microhairs absent. Stomata fairly common; about 45 microns long. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells absent or very rare. Costal short-cells neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies horizontally-elongated crenate/sinuous (but so deeply ‘crenate’ as almost to qualify as ‘nodular’).
Transverse section of leaf blade, physiology. XyMS+.
Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid.
Taxonomy. Pooideae; Poodae; Aveneae.
Distribution, ecology, phytogeography. 2 species; Mediterranean.
Holarctic. Boreal and Tethyan. Euro-Siberian. Mediterranean. European.
References, etc. Leaf anatomical: this project.
Special comments. Anatomical data epidermal only.
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).