Mibora Adans.
Including Chamagrostis Borkh., Knappia Sm., Micagrostis Juss., Rothia Borkh., Sturmia Hoppe
Habit, vegetative morphology. Diminutive annual; caespitose. Culms 2–15 cm high (filiform); herbaceous. Leaves mostly basal; non-auriculate. Leaf blades linear; narrow; 0.3–1 mm wide; flat, or folded; without cross venation; persistent; an unfringed membrane; truncate; 0.5–1.5 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence a single raceme (unilateral, spikelike); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; secund; distichous; shortly pedicellate.
Female-fertile spikelets. Spikelets 1.8–3 mm long; compressed laterally; disarticulating above the glumes. Rachilla terminated by a female-fertile floret. Hairy callus absent. Callus very short.
Glumes two; more or less equal; exceeding the spikelets; long relative to the adjacent lemmas; not pointed (obtuse to emarginate); awnless; non-carinate; similar (thinly membranous). Lower glume 1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas less firm than the glumes (hyaline); not becoming indurated; entire to incised (truncate-denticulate); awnless; hairy; non-carinate; 5 nerved. Palea present; relatively long; awnless, without apical setae (hairy); 2-nerved; keel-less. Lodicules present; 2. Stamens 3. Anthers 1.4–1.7 mm long; not penicillate. Ovary glabrous. Styles fused. Stigmas 2.
Fruit, embryo and seedling. Fruit free from both lemma and palea; small. Hilum short. Embryo small. Endosperm liquid in the mature fruit, or hard; with lipid.
Seedling with a loose coleoptile. First seedling leaf with a well-developed lamina. The lamina narrow; 1–3 veined.
Abaxial leaf blade epidermis. Costal/intercostal zonation lacking. Papillae absent. Mid-intercostal long-cells fusiform; 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 (none seen). Costal silica bodies absent.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade with distinct, prominent adaxial ribs; with the ribs more or less constant in size. Midrib conspicuous; with one bundle only. Bulliforms not present in discrete, regular adaxial groups (no bulliform cells). Many of the smallest vascular bundles unaccompanied by sclerenchyma. Combined sclerenchyma girders absent. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid. Chromosomes ‘large’. Haploid nuclear DNA content 2.8 pg (1 species, 2x). Mean diploid 2c DNA value 5.5 pg.
Taxonomy. Pooideae; Poodae; Aveneae.
Distribution, ecology, phytogeography. 2 species; Mediterranean. Commonly adventive. Mesophytic; species of open habitats. Damp, sandy soils.
Holarctic. Boreal and Tethyan. Euro-Siberian. Mediterranean. European.
References, etc. Leaf anatomical: this project.
Illustrations. • General aspect, spikelet. • Abaxial epidermis of leaf blade. Mibora minima.
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).
