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The grass genera of the world

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

Melocanna Trin.

Including Beesha Kunth

Habit, vegetative morphology. Perennial (shrubs or trees); rhizomatous. The flowering culms leafy. Culms 1000–2000 cm high; woody and persistent; to 9 cm in diameter; branched above. Primary branches 4–20. The branching dendroid. Culm leaf sheaths present; deciduous, or persistent; not leaving a persistent girdle; not conspicuously auriculate. Culm leaves with conspicuous blades. Culm leaf blades linear. Culm internodes hollow. Rhizomes pachymorph (metamorph type II). Plants unarmed. Leaves not basally aggregated; auricles inconspicuous; without auricular setae. Leaf blades broad; 20–90 mm wide; pseudopetiolate; without cross venation; disarticulating from the sheaths; rolled in bud. Contra-ligule absent.

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

Inflorescence. Inflorescence indeterminate; with pseudospikelets; paniculate (large, compound, with spatheate, oblong, tight groups of few to several spikelets imbricate and secund on the branches); spatheate (the spikelet fascicles bracteate); a complex of ‘partial inflorescences’ and intervening foliar organs. Spikelet-bearing axes paniculate; persistent. Spikelets secund (the fascicles secund on the spicate inflorescence branches).

Female-fertile spikelets. Spikelets unconventional; 10–15 mm long; disarticulating above the glumes (?); disarticulating between the florets (?). Rachilla prolonged beyond the uppermost female-fertile floret, or terminated by a female-fertile floret.

Glumes two to several (to four); shorter than the adjacent lemmas; pointed; awnless; similar (ovate-lanceolate). Spikelets presumably? with incomplete florets. The incomplete florets proximal to the female-fertile florets (assuming the ‘several glumes’ may represent sterile lemmas). Spikelets with proximal incomplete florets (?). The proximal incomplete florets 1–2 (?); sterile.

Female-fertile florets 1. Lemmas ovate-lanceolate, pungent; less firm than the glumes to similar in texture to the glumes; entire; pointed; awnless. Palea present; relatively long; several nerved (?); keel-less. Lodicules present; 2; free; membranous (narrow); ciliate; heavily vascularized (3–5 nerved). Stamens 5–7; with free filaments, or monadelphous to triadelphous (then irregularly united). Anthers not penicillate; without an apically prolonged connective. Ovary apically glabrous; with a conspicuous apical appendage. The appendage long, stiff and tapering. Styles fused (ovary attenuate into a long style). Stigmas 2–4 (feathery, recurved).

Fruit, embryo and seedling. Fruit large (reaching 7–12 cm long in M. baccifera); pyriform. Pericarp fleshy. Embryo large (but not visible). Seed ‘non-endospermic’ (or hardly so, when mature: the abnormally large scutellum absorbs nearly all the endosperm, and the seed germinates while fruit still attached to parent plant). Embryo with an epiblast; with a scutellar tail; with a negligible mesocotyl internode. Embryonic leaf margins overlapping.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present (confined to stomatal bands). Intercostal papillae over-arching the stomata. Intercostal zones with typical long-cells to exhibiting many atypical long-cells (the long-cells short). Mid-intercostal long-cells having markedly sinuous walls (thin). Microhairs present; panicoid-type; 63–66 microns long (in M. bambusoides); 6–7.5 microns wide at the septum. Microhair total length/width at septum 8.4–11. Microhair apical cells 33.6–37.5 microns long. Microhair apical cell/total length ratio 0.52–0.57. Stomata common (obscured by papillae); 24–27 microns long (in M. bambusoides). Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies tall-and-narrow. Costal short-cells predominantly paired (occasionally in short rows). Costal silica bodies saddle shaped; not sharp-pointed.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with arm cells; with fusoids (conspicuous). The fusoids external to the PBS. Leaf blade with distinct, prominent adaxial ribs (ribs slight, widely spaced), or adaxially flat; with the ribs more or less constant in size. Midrib conspicuous; having complex vascularization. Bulliforms present in discrete, regular adaxial groups; in simple fans (mostly), or associated with colourless mesophyll cells to form deeply-penetrating fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with most bundles); forming ‘figures’ (many bundles, somewhat so).

Classification. Watson & Dallwitz (1994): Bambusoideae; Bambusodae; Bambuseae. Soreng et al. (2015): Bambusoideae; Bambusodae; Bambuseae; Melocanninae. 3 species.

Distribution, phytogeography, ecology. Eastern Asia.

Economic aspects. Culms of M. baccifera yield pulp for high quality papers; splits are used in handicrafts; and the large fruits are edible.

References, etc. Leaf anatomical: Metcalfe 1960; studied by us - M. bambusoides Trin.

Illustrations. • M. baccifera: Maclure (1955), Grasses of Guatemala 24, II

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: 11th December 2017.’.