Ochlandra Thwaites
Including Beesha Munro, Irulia Bedd.
Habit, vegetative morphology. Perennial; reeds, or not reeds (shrubs). The flowering culms leafy. Culms 200–600 cm high; woody and persistent; to 5 cm in diameter. Culm sheaths persistent. Culm internodes hollow. Plants unarmed. Leaves not basally aggregated; auriculate (with pellucid dots); without auricular setae. Leaf blades broad; pseudopetiolate; disarticulating from the sheaths; an unfringed membrane; truncate; short.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence indeterminate; with pseudospikelets; a false spike, with spikelets on contracted axes (the clusters stellate); spatheate, or espatheate. Spikelet-bearing axes capitate. Spikelets not secund.
Female-fertile spikelets. Spikelets 18–50 mm long; not noticeably compressed; falling with the glumes. Rachilla terminated by a female-fertile floret; hairless.
Glumes present; two; more or less equal; shorter than the adjacent lemmas; hairless; pointed; awnless (but shortly mucronate); non-carinate; similar. Lower glume much shorter than half length of lowest lemma; 40 nerved (or more, in material seen). Upper glume 40 nerved (or more, in material seen). Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1–3; sterile. The proximal lemmas awnless (but shortly mucronate); 40 nerved (or more, in material seen); exceeded by the female-fertile lemmas; similar in texture to the female-fertile lemmas; not becoming indurated.
Female-fertile florets 1. Lemmas similar in texture to the glumes; not becoming indurated; entire; pointed; non-carinate; without a germination flap; 40 nerved (or more, in material seen). Palea present; relatively long; entire, or apically notched, or deeply bifid; awnless, without apical setae; not indurated; several nerved (9 or more in material seen); keel-less. Lodicules present; 1–5(–15); free; membranous; glabrous; toothed, or not toothed; heavily vascularized (sometimes up to 15 mm long). Stamens 6–120; with free filaments to monadelphous. Anthers not penicillate; with the connective apically prolonged. Ovary glabrous; with a conspicuous apical appendage. The appendage long, stiff and tapering. Styles fused. Stigmas 3–6.
Fruit, embryo and seedling. Fruit free from both lemma and palea; large (2–5 cm long); ellipsoid, or subglobose, or pyriform; not noticeably compressed. Hilum not visible. Pericarp fleshy. Embryo not visible. Seed ‘non-endospermic’.
Seedling with a short mesocotyl; with a loose coleoptile. First seedling leaf without a lamina.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present. Intercostal papillae over-arching the stomata (and obscuring them); several per cell (often one row per long-cell). Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type; 54–60 microns long; 7.5–9–10.5 microns wide at the septum. Microhair total length/width at septum 5.1–7.4. Microhair apical cells 25.5–30 microns long. Microhair apical cell/total length ratio 0.47–0.54. Stomata common (obscured papillae and sunken); 22.5–27 microns long. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Costal short-cells predominantly paired, or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies saddle shaped, or crescentic (e.g. predominant in O. stridula); not sharp-pointed.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade; with arm cells; with fusoids. The fusoids external to the PBS. Leaf blade adaxially flat. Midrib conspicuous; having complex vascularization. The lamina distinctly asymmetrical on either side of the midrib. Bulliforms present in discrete, regular adaxial groups; in simple fans (the median cells deeply penetrating). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with most bundles); forming ‘figures’ (with most bundles). Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 12. 2n = 72. 6 ploid.
Taxonomy. Bambusoideae; Bambusodae; Bambuseae.
Distribution, ecology, phytogeography. 12 species; Madagascar, India, Ceylon. Forest thickets.
Paleotropical. Madagascan and Indomalesian. Indian.
References, etc. Leaf anatomical: Metcalfe 1960; 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).