The grass genera of the world
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. Ligule a fringed membrane (and sometimes double, with the usual short membrane backed by a larger one). Contra-ligule present.
Reproductive organization. Plants bisexual, all 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. Third lodicule present (the posterior smaller). Lodicules free; membranous; ciliate to glabrous; not toothed. Stamens 3–6. Anthers not penicillate; without an apically prolonged connective. Ovary apically 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.
Classification. Watson & Dallwitz (1994): Bambusoideae; Bambusodae; Bambuseae. Soreng et al. (2015): Bambusoideae; Bambusodae; Bambuseae; Chusqueinae. 9 species.
Distribution, phytogeography, ecology. South America (Venezuela to Peru), Trinidad.
References, etc. Morphological/taxonomic: Soderstrom 1969. Leaf anatomical: Metcalfe 1960.
Illustrations. • N. aristata and N. magnifolia (as N. pittieri): McClure, New World Bamboos (1973). • N. elata (as Platonia: Kunth (1835)
We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or the interactive key, which allows access to the character list, illustrations, full and partial descriptions, diagnostic descriptions, differences and similarities between taxa, lists of taxa exhibiting or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.
Cite this publication as: ‘Watson, L., Macfarlane, T.D., and Dallwitz, M.J. 1992 onwards. The 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. Version: 13th November 2017. delta-intkey.com/grass’.