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The grass genera of the world

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

Soejatmia K.M. Wong

~ Bambusa

Type species: S. ridleyi (Gamble) Wong.

Habit, vegetative morphology. Perennial; rhizomatous and caespitose. Culms 300–500 cm high; without nodal roots, woody and persistent; cylindrical; branched above. Buds from which the primary culm branches arise 1. Primary branches 3; clumped (in untidy tufts). The branching dendroid. Culm nodes hairy. Culm leaf sheaths present; conspicuously auriculate. Culm leaves with conspicuous blades. Culm leaf blades ovate. Culm internodes glabrous, 20–45 cm long, hollow. Rhizomes pachymorph. Leaves not basally aggregated; conspicuously auriculate (the auricles erect); with auricular setae. Leaf blades lanceolate; broad; 20–30 cm long, 25–50 mm wide; pseudopetiolate. Contra-ligule present.

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

Inflorescence. Inflorescence indeterminate; with pseudospikelets (subtended by glumaceous bracts smaller than the lemmas, with axillary buds at the bases of the spikelets, and prophylls below the lateral spikelets); comprising bractiferous nodal clusters; a complex of ‘partial inflorescences’ and intervening foliar organs. Spikelets not secund; sessile.

Female-fertile spikelets. Spikelets unconventional; 40–50 mm long; lanceolate; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with distinctly elongated rachilla internodes between the florets (5–7 mm long). Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets.

Glumes present; one per spikelet, or several (depending whose description you believe). Spikelets with incomplete florets. The incomplete florets both distal and proximal to the female-fertile florets (there being a ‘transitional glume’ subtending a sterile floret beneath the empty one). The distal incomplete florets 1–2; merely underdeveloped; awnless. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; paleate; sterile. The proximal lemmas awnless.

Female-fertile florets 3–5. Lemmas lanceolate, 18–22 mm long; convolute; entire; pointed; mucronate; hairless; non-carinate. Palea present; relatively long; tightly clasped by the lemma; deeply bifid; with apical setae (the shortish pair of projections often hooked); several nerved (many - 12–16); 2-keeled. Palea keels hairy. Lodicules present; 8–9 mm long, 3; free; membranous; ciliate; not toothed. Stamens 6; with free filaments. Anthers with the connective apically prolonged. Ovary apically hairy; with a conspicuous apical appendage. The appendage broadly conical, fleshy. Styles fused. Stigmas 3.

Fruit, embryo and seedling. Pericarp thin.

Classification. Watson & Dallwitz (1994): not described separately. Soreng et al. (2015): Bambusoideae; Bambusodae; Bambuseae; Bambusinae. 1 species (S. ridleyi).

Distribution, phytogeography, ecology. Southern Malay Peninsula.

References, etc. Morphological/taxonomic: Clayton et al. (2016), Grassbase; K. M. Wong (1993): Four New Genera of Bamboos (Gramineae: Bambusoideae) from Malesia. Kew Bulletin 48, 517–532.

Special comments. Anatomical data wanting. Illustrations. • S. ridleyi, as Bambusa: Gamble, Bambuseae of Br. India (1896)


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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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