| # The grass genera of the world |

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

### Bonia Balansa

~ Bambusa

Including Monocladus

Habit, vegetative morphology. Perennial. The flowering culms leafy. Culms 100–2600 cm high; woody and persistent (without nodal roots); to 4–12 cm in diameter; cylindrical; not scandent; clump-forming, self-supporting, or scrambling; branched above. Primary branches nearly as thick as the culms, 1 (in B. parvifloscula), or 4–20 (B. tonkinensis). The branching suffrutescent (in ‘B. levigata’), or dendroid. Culm leaf sheaths present; deciduous; conspicuously auriculate, or not conspicuously auriculate. Culm leaves with conspicuous blades. Culm leaf blades lanceolate, or ovate. Culm internodes solid to hollow. Rhizomes short, pachymorph. Leaves auriculate, or non-auriculate; without auricular setae. Leaf blades linear-lanceolate to lanceolate, or elliptic; broad; 11–35 cm long, 15–60 mm wide; pseudopetiolate; without cross venation. Ligule a fringed membrane.

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

Inflorescence. Inflorescence indeterminate; with pseudospikelets; "comprising nodal clusters of untidily tufted synflorescences"; spatheate; a complex of ‘partial inflorescences’ and intervening foliar organs.

Female-fertile spikelets. Spikelets unconventional; 12–30 mm long; lanceolate, or ovate, or linear; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with a distinctly elongated rachilla internode above the glumes and with distinctly elongated rachilla internodes between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; the rachilla extension with incomplete florets.

Glumes poorly described, present, or absent (gemmiferous bracts only in B. parvifloscula); if present, two, or several; muticous or mucronate, awnless. Lower glume in B. solida, 11 nerved. Upper glume in B. solida, 11 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped; awnless. Spikelets without proximal incomplete florets.

Female-fertile florets 3–9. Lemmas lanceolate or oblong; similar in texture to the glumes to decidedly firmer than the glumes; smooth; not becoming indurated; entire; apiculate, awnless to mucronate; hairy, or hairless; non-carinate; 7 nerved. Palea present; relatively long and conspicuous but relatively short (the one accompanying the proximal lemma exceeding it, those of the upper florets much shorter than the lemmas); membranous, thinner than the lemma; several nerved (6–10); 2-keeled (?). Palea back glabrous to hairy. Palea keels wingless; glabrous to hairy. Lodicules present; 3; membranous; glabrous; toothed to not toothed (emarginate). Stamens 6; with free filaments. Ovary apically glabrous; with a conspicuous apical appendage, or without a conspicuous apical appendage. The appendage if appendaged, broadly conical, fleshy. Styles very short. Stigmas 3.

Fruit, embryo and seedling. Fruit not grooved; glabrous. Pericarp thin (?); fused.

Classification. Watson & Dallwitz (1994): genus not recognised. Soreng et al. (2015): Bambusoideae; Bambusodae; Bambuseae; Bambusinae. 5 species (3 from vegetative material only).

Distribution, phytogeography, ecology. China, Vietnam.

References, etc. Morphological/taxonomic: Clayton et al., GrassBase; FOC vol. 22.

Special comments. This unsatisfactory compilation from poor descriptions (q.v.) excludes species described from non-flowering material. Anatomical data wanting.

Illustrations. • Bonia tonkinensis, with Fargesia and Oreiostachys: Camus (1913). • Camus legend.

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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