Grass Genera of the World

L. Watson and M. J. Dallwitz


Neurolepis Meissner

Including Planotia Munro, Platonia Kunth

Habit, vegetative morphology. Grasslike perennial; caespitose. The flowering culms leafy. Culms 100–550 cm high; woody and persistent to herbaceous; to 2.6 cm in diameter; unbranched above. Culm nodes glabrous. Culm internodes hollow. Unicaespitose (usually), or pluricaespitose (e.g. N. aristata). Rhizomes pachymorph. Plants unarmed. Leaves not basally aggregated. Leaf blades linear; broad, or narrow (typically coarse, grass-like); sometimes very large: up to 30 cm wide and 5 m long in N. elata; pseudopetiolate, or not pseudopetiolate; cross veined, or without cross venation; disarticulating from the sheaths, or persistent; a fringed membrane (and sometimes double, with the usual short membrane backed by a larger one). Contra-ligule present.

Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.

Inflorescence. Inflorescence paniculate (each terminating an unbranched culm); open, or contracted (elongated, broadly to narrowly paniculate, with a strong rachis). Inflorescence with axes ending in spikelets, or axes not ending in spikelets. Inflorescence espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes ‘racemes’ to spikelike; persistent. Spikelets solitary; secund to not secund (‘commonly only one order of the branches...showing secund orientation’); pedicellate.

Female-fertile spikelets. Spikelets not noticeably compressed; disarticulating above the glumes; not disarticulating between the florets, or disarticulating between the florets. Rachilla terminated by a female-fertile floret; hairless. Hairy callus absent.

Glumes present; two; more or less equal; shorter than the adjacent lemmas; hairless; not pointed; awnless; non-carinate; similar. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 2–3; sterile. The proximal lemmas awnless; more or less equalling the female-fertile lemmas; similar in texture to the female-fertile lemmas.

Female-fertile florets 1. Lemmas entire; blunt; awnless; hairless; non-carinate; 3–7 nerved. Palea present; relatively long; entire to apically notched; awnless, without apical setae; 2-nerved; keel-less. Lodicules present; 3; free; membranous; ciliate to glabrous; not toothed. Stamens 3–6. Anthers not penicillate; without an apically prolonged connective. Ovary glabrous; without a conspicuous apical appendage. Styles fused. Stigmas 2.

Fruit, embryo and seedling. Fruit free from both lemma and palea; small. Hilum long-linear. Embryo small (‘basal, clearly to weakly manifest’).

Abaxial leaf blade epidermis. Papillae present. Intercostal papillae over-arching the stomata, or not over-arching the stomata; several per cell. Long-cells similar in shape costally and intercostally. Microhairs present; panicoid-type; 42–66(–70) microns long. Microhair apical cells 16–21 microns long (N. aristata), or 10–40 microns long (N. nobilis). Microhair apical cell/total length ratio 0.3 (N. aristata), or 0.46 (N. nobilis). Stomata common. Subsidiaries low to high dome-shaped. Intercostal short-cells absent or very rare (rarely). Costal short-cells predominantly paired (and solitary). Costal silica bodies rounded, or tall-and-narrow (sometimes tall-narrow-crenate), or crescentic; not sharp-pointed.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; with arm cells; with fusoids. The fusoids external to the PBS. Midrib not readily distinguishable; having complex vascularization (sometimes obscure). Bulliforms present in discrete, regular adaxial groups; associated with colourless mesophyll cells to form deeply-penetrating fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’.

Cytology. Chromosome base number, x = 12. 2n = 48. 4 ploid.

Taxonomy. Bambusoideae; Bambusodae; Bambuseae.

Distribution, ecology, phytogeography. 9 species; South America (Venezuela to Peru), Trinidad.

Neotropical. Venezuela and Surinam and Andean.

References, etc. Morphological/taxonomic: Soderstrom 1969. Leaf anatomical: Metcalfe 1960.


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).

Index