| # The grass genera of the world |

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

### Melocalamus Benth.

Excluding Dinochloa

Habit, vegetative morphology. Perennial. The flowering culms leafy. Culms 500–3000 cm high; woody and persistent; scandent (tufted, spreading, arching); branched above. Buds from which the primary culm branches arise (where recorded) 1. Primary branches (1–)4–20. The branching dendroid. Culm leaf sheaths present; deciduous, or persistent; leaving a persisten girdle (occasionally), or not leaving a persistent girdle; conspicuously auriculate, or not conspicuously auriculate. Culm leaves with conspicuous blades. Culm leaf blades linear, or lanceolate, or ovate, or triangular. Culm internodes hollow. Rhizomes pachymorph. Plants unarmed. Leaves not basally aggregated; auriculate (the auricles hirsute, reflexed, caducous); with auricular setae. Leaf blades lanceolate to elliptic; broad; 22–50 mm wide (and 14–26 cm long); not cordate, not sagittate (rounded at base); pseudopetiolate (the petiolule hairy); without cross venation; disarticulating from the sheaths; rolled in bud. Ligule present (narrow, entire). Contra-ligule present, or absent (usually).

Reproductive organization. Plants bisexual, all with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; hermaphrodite and sterile (panicle ‘with several fertile and many sterile spikelets’). Sometimes viviparous.

Inflorescence. Inflorescence indeterminate; with pseudospikelets; paniculate (a large, compound, interrupted panicle of small sub-globose heads); spatheate; a complex of ‘partial inflorescences’ and intervening foliar organs (the panicle often leafy). Spikelet-bearing axes capitate; persistent. Spikelets not secund; not in distinct ‘long-and-short’ combinations.

Female-fertile spikelets. Spikelets unconventional; 1.7–2.5 mm long; obovate (usually), or suborbicular; disarticulating above the glumes (?); disarticulating between the florets (?); with conventional internode spacings. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets.

Glumes two; more or less equal; shorter than the adjacent lemmas; hairless; awnless (shortly mucronate); similar (broadly oval, ventricose). Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets 1; merely underdeveloped.

Female-fertile florets 2. Lemmas similar in texture to the glumes; not becoming indurated; entire; awnless, or mucronate (?); fertile lemma often ciliate on margins. Palea present; relatively long; convolute around the flower, or not convolute; apically notched; awnless, without apical setae; not indurated; several nerved (4–5 nerves between the keels); 2-keeled. Palea keels hairy (ciliate). Lodicules present (large); 3; free; membranous; ciliate; not toothed (blunt); heavily vascularized. Stamens 6; with free filaments (these short). Ovary apically glabrous; without a conspicuous apical appendage. Styles fused. Stigmas 2, or 3 (short, plumose).

Fruit, embryo and seedling. Fruit large (2.25–3 cm in diameter); subglobose. Pericarp fleshy; free. Seed ‘non-endospermic’.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present. Intercostal papillae over-arching the stomata (four or more overarching each stoma). Long-cells markedly different in shape costally and intercostally (the costals rather longer). Intercostal zones exhibiting many atypical long-cells (a short form). Mid-intercostal long-cells having markedly sinuous walls. Microhairs present; panicoid-type. Stomata common (obscured by papillae). Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies vertically elongated-nodular. Costal short-cells predominantly paired. Costal silica bodies saddle shaped (mostly, tall), or tall-and-narrow; not sharp-pointed.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with arm cells; with fusoids. Leaf blade adaxially flat (save near midrib). Midrib conspicuous; having complex vascularization. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with all the bundles); forming ‘figures’ (larger bundles with this tendency).

Classification. Watson & Dallwitz (1994): Bambusoideae; Bambusodae; Bambuseae. Soreng et al. (2015): Bambusoideae; Bambusodae; Bambuseae; Bambusinae. 1 species (M. compactiflorus).

Distribution, phytogeography, ecology. India, Burma.

Forests.

References, etc. Leaf anatomical: Metcalfe 1960, and studied by us.

Special comments. Fruit data wanting.

Illustrations. • Melocalamus compactiflorus, with Puelia ciliata and Pseudostachyum polymorphum (Camus, 1913). • Abbreviations for Camus (1913) figures.

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: 15th June 2025. delta-intkey.com’.

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