Coleanthus Seidl.
From the Greek koleos (sheath) and anthos (flower), referring to a sheath at the base of the panicle.
Including Schmidtia Tratt., Wilibalda Roth
Habit, vegetative morphology. Dwarf annual; decumbent. Culms 2–10 cm high; herbaceous. Leaves non-auriculate. Sheath margins joined. Sheaths inflated. Leaf blades linear (usually recurved); narrow; about 1 mm wide; flat, or folded; without cross venation; ligule present; an unfringed membrane; 1–1.5 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality.
Inflorescence. Inflorescence paniculate (subtended by the expanded sheath of the upper leaf, the branches in compact, globular fascicles); contracted; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent (?). Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets unconventional (in lacking glumes); 0.75–1.5 mm long; not noticeably compressed; disarticulating under the lemma. Rachilla terminated by a female-fertile floret. Hairy callus absent. Callus short.
Glumes absent. Spikelets with female-fertile florets only.
Female-fertile florets 1. Lemmas not becoming indurated (membranous or hyaline); entire; pointed; awned. Awns 1; median; apical (from the caudate- or aristate-acuminate lemma); non-geniculate; entered by one vein. Lemmas hairless (but ciliate on the keel); carinate; without a germination flap; 1 nerved. Palea present; conspicuous but relatively short; not indurated (membranous); 2-nerved; 2-keeled. Lodicules absent. Stamens 2. Anthers 0.3–0.4 mm long. Ovary glabrous. Styles free to their bases (very long). Stigmas 2; white.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small (1.5 mm long). Hilum short (oval). Embryo small. Endosperm hard; without lipid; containing compound starch grains. Embryo with an epiblast; without a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins meeting.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells differing markedly in wall thickness costally and intercostally. Intercostal zones with typical long-cells (but seemingly lacking short-cells). Mid-intercostal long-cells having straight or only gently undulating walls. Microhairs absent. Stomata common. Subsidiaries parallel-sided. Guard-cells overlapped by the interstomatals. Intercostal short-cells absent or very rare. Costal zones seemingly without short-cells (in the material seen). Costal silica bodies absent.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll without adaxial palisade. Leaf blade adaxially flat. Midrib conspicuous (mainly by its position); with one bundle only. The lamina symmetrical on either side of the midrib. Bulliforms not present in discrete, regular adaxial groups (apart from midrib hinges). Many of the smallest vascular bundles unaccompanied by sclerenchyma (all bundles unaccompanied by sclerenchyma, in the material seen).
Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid. Chromosomes ‘large’.
Taxonomy. Pooideae; Poodae; Poeae.
Distribution, ecology, phytogeography. 1 species; North temperate. Helophytic to mesophytic (in dried up lakes and reservoirs, at pond margins); glycophytic.
Holarctic. Boreal and Tethyan. Euro-Siberian. Mediterranean. European.
Rusts and smuts. Rusts — Puccinia. Taxonomically wide-ranging species: Puccinia graminis.
References, etc. Leaf anatomical: Metcalfe 1960; 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).