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The grass genera of the world

L. Watson, T.D. Macfarlane, and M.J. Dallwitz

Reynaudia Kunth

Habit, vegetative morphology. Perennial; caespitose. Culms 15–40 cm high; herbaceous; unbranched above. Culm nodes hairy. Leaves mostly basal; non-auriculate. Leaf blades narrow (slender); rolled (involute); without cross venation; persistent.

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

Inflorescence. Inflorescence paniculate; contracted (rather narrow, 3–6 cm long); espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets pedicellate.

Female-fertile spikelets. Spikelets 3–4 mm long; compressed laterally; falling with the glumes. Rachilla terminated by a female-fertile floret. Hairy callus absent (?).

Glumes present; two; very unequal; (the upper) shorter than the spikelets to about equalling the spikelets (the upper about half as long); the upper shorter than the adjacent lemmas to long relative to the adjacent lemmas (sometimes little shorter than the spikelet); hairless; awned (both long-awned from between the lobes of the bifid apex); carinate; firmly membranous. Lower glume strongly 3 nerved, or 5 nerved. Upper glume strongly 5 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; sterile. The proximal lemmas awned (shortly, from the apical notch), or awnless (but then mucronate); 3 nerved; decidedly exceeding the female-fertile lemmas; decidedly firmer than the female-fertile lemmas (similar to the glumes).

Female-fertile florets 1. Lemmas less firm than the glumes; thin; not deeply cleft; awnless, or mucronate (the nerve excurrent from the keel); carinate; without a germination flap; 5 nerved (with 2 pairs of obscure laterals). Palea absent. Lodicules absent (?). Stamens 2.

Fruit, embryo and seedling. Fruit ellipsoid; compressed dorsiventrally.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally (but the costals smaller and narrower); of similar wall thickness costally and intercostally (walls of medium thickness). Mid-intercostal long-cells rectangular; having markedly sinuous walls (pitted). Microhairs present; panicoid-type; 48–54–60 microns long; (9–)9.3–9.9(–10.2) microns wide at the septum. Microhair total length/width at septum 4.8–6.7. Microhair apical cells (27–)33–36(–39) microns long. Microhair apical cell/total length ratio 0.56–0.67. Stomata common; 27(–30) microns long. Subsidiaries triangular; including both triangular and parallel-sided forms on the same leaf. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies crescentic. Costal short-cells predominantly paired. Costal silica bodies rounded (a few), or tall-and-narrow (very few), or crescentic (predominating); not sharp-pointed.

Transverse section of leaf blade, physiology. C4; XyMS–. Mesophyll without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs; with the ribs more or less constant in size (round-topped). Midrib not readily distinguishable; with one bundle only; with colourless mesophyll adaxially (each rib with an adaxial group of large colourless cells). Bulliforms present in discrete, regular adaxial groups; in simple fans (these small, in each furrow). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders absent (each bundle with a wide, narrow adaxial strand and an abaxial girder). Sclerenchyma all associated with vascular bundles.

Classification. Watson & Dallwitz (1994): Panicoideae; Panicodae; Paniceae (Arthropogoneae). Soreng et al. (2015): Panicoideae; Panicodae; Paspaleae. 1 species.

Distribution, phytogeography, ecology. West Indies.

Mesophytic; species of open habitats. Savanna, palm barrens, bushy slopes.

References, etc. Leaf anatomical: this project.

Special comments. Fruit data wanting. Illustrations. • R. filiformis: Kunth (1835). • R. filiformis: Hitchcock (1936)


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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’.

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