Micropyrum Link
Habit, vegetative morphology. Annual. Culms 50–100 cm high; herbaceous. Leaves non-auriculate. Sheath margins free. Leaf blades linear; narrow; flat, or rolled (convolute when dry); without cross venation; an unfringed membrane; truncate; 0.2–1 mm long.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets all alike in sexuality.
Inflorescence. Inflorescence a single raceme (spiciform), or paniculate (sparingly branched); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; when in a raceme, distichous; pedicellate.
Female-fertile spikelets. Spikelets 4–16 mm long; compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets. Hairy callus absent.
Glumes two; very unequal to more or less equal; shorter than the adjacent lemmas; dorsiventral to the rachis; pointed, or not pointed (acute to rounded); awnless; carinate, or non-carinate; similar (leathery). Lower glume 1–3 nerved. Upper glume 3–5 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. Spikelets without proximal incomplete florets.
Female-fertile florets 3–9(–14). Lemmas decidedly firmer than the glumes (papery); not becoming indurated; entire to incised (obtuse to emarginate); awnless (but apiculate), or mucronate, or awned. Awns when present, 1; 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 (dorsally rounded); without a germination flap; 5 nerved. Palea present; relatively long; apically notched (shortly bifid); awnless, without apical setae; 2-nerved; 2-keeled. Lodicules present; 2; free; membranous; glabrous; toothed; not or scarcely vascularized. Stamens 3. Anthers 0.5–3.2 mm long. Ovary glabrous; without a conspicuous apical appendage. Styles free to their bases. Stigmas 2.
Fruit, embryo and seedling. Fruit adhering to lemma and/or palea; medium sized (2.5–3.2 mm long); not grooved; compressed dorsiventrally. Hilum long-linear. Embryo small. Endosperm hard; without lipid; containing compound starch grains. Embryo with an epiblast.
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; having markedly sinuous walls (and pitted). Microhairs absent. Stomata absent or very rare. Intercostal short-cells absent or very rare. Costal short-cells predominantly paired. Costal silica bodies rounded (numerous); not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Leaf blade with distinct, prominent adaxial ribs; with the ribs more or less constant in size. Midrib not readily distinguishable; with one bundle only. Bulliforms poorly defined, in the poor material seen. Combined sclerenchyma girders absent. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 7. 2n = 14. 2 ploid.
Taxonomy. Pooideae; Poodae; Poeae.
Distribution, ecology, phytogeography. 3 species; Central Europe, Mediterranean. Species of open habitats. Dry places.
Holarctic. Boreal and Tethyan. Euro-Siberian. Mediterranean. European.
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).