Microcalamus Franch.
Habit, vegetative morphology. Perennial; rhizomatous and stoloniferous. Culms 15–60 cm high; herbaceous; unbranched above. Culm nodes hairy. Young shoots extravaginal. Leaves not basally aggregated; non-auriculate. Leaf blades lanceolate to ovate; broad; 15–50 mm wide; not cordate, not sagittate; pseudopetiolate; cross veined; persistent; ligule present; an unfringed membrane, or a fringed membrane (laciniate, minutely fringed).
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence paniculate; open, or contracted (about the primary branches); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate.
Female-fertile spikelets. Spikelets weakly compressed laterally; falling with the glumes. Rachilla terminated by a female-fertile floret. Hairy callus present.
Glumes two; very unequal; shorter than the adjacent lemmas; hairless; pointed; awnless; non-carinate; similar (ovate, papery). Lower glume 5–7 nerved. Upper glume 5–7 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; paleate. Palea of the proximal incomplete florets fully developed. The proximal incomplete florets sterile. The proximal lemmas awnless; 7 nerved; somewhat exceeded by the female-fertile lemmas; less firm than the female-fertile lemmas (papery, similar to the glumes); not becoming indurated.
Female-fertile florets 1. Lemmas rostrate or subulate; similar in texture to the glumes to decidedly firmer than the glumes (subleathery); not becoming indurated; entire; pointed; crested at the tip; awnless (but beaked); hairy; non-carinate; having the margins lying flat on the palea; without a germination flap; 5 nerved. Palea present; relatively long; entire; 2-nerved; 2-keeled. Lodicules present; 2; free; fleshy; glabrous; not or scarcely vascularized. Stamens 3. Anthers not penicillate; without an apically prolonged connective. Ovary glabrous. Styles fused. Stigmas 2; white (in dried material).
Fruit, embryo and seedling. Hilum short.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Intercostal zones exhibiting many atypical long-cells. Mid-intercostal long-cells having straight or only gently undulating walls. Microhairs present; panicoid-type. Stomata common (but very localised, in one or two rows adjoining veins). Subsidiaries triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’; mostly cross shaped; not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma. Leaf blade adaxially flat. Midrib conspicuous (keel, large bundle); with one bundle only. Bulliforms not present in discrete, regular adaxial groups (constituting most of epidermis). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (midrib bundle only); forming ‘figures’ (in the midrib). Sclerenchyma all associated with vascular bundles.
Taxonomy. Panicoideae; Panicodae; Paniceae.
Distribution, ecology, phytogeography. 4 species; tropical west Africa. Shade species; glycophytic. In forest.
Paleotropical. African. West African Rainforest.
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).