| # The grass genera of the world |

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

### Holttumochloa K.M. Wong

~ Bambusa

Habit, vegetative morphology. Perennial; shortly rhizomatous and caespitose. The flowering culms leafy. Culms 300–500 cm high; woody and persistent (without nodal roots); to 4–4.6 cm in diameter; cylindrical; branched above. Buds from which the primary culm branches arise 5–20 (? - ‘many’). Primary branches the bud prophylls multi-lobed, 11–20 (the branches subequal); clumped. The branching dendroid. Culm leaf sheaths present; where recorded, conspicuously auriculate. Culm leaves where recorded, with conspicuous blades. Culm leaf blades lanceolate. Rhizomes pachymorph. Leaves non-auriculate. Leaf blades lanceolate; 3.5–11 cm long, 4–10 mm wide; shortly pseudopetiolate. Ligule an unfringed membrane, or a fringed membrane. Contra-ligule present, or absent.

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

Inflorescence. Inflorescence indeterminate; with pseudospikelets (these borne in clusters on branches that themselves remain unbranched, with glumaceous or leafy subtending bracts that are smaller than the lemmas and axillary buds at the spikelet bases); a complex of ‘partial inflorescences’ and intervening foliar organs. Spikelets not secund.

Female-fertile spikelets. Spikelets unconventional; 10–25 mm long; lanceolate; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with distinctly elongated rachilla internodes between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; hairy, or hairless; the rachilla extension with incomplete florets.

Glumes one per spikelet, or two to several (description ambiguous); shorter than the spikelets; shorter than the adjacent lemmas. Lower glume not pitted. 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 2–4. Lemmas lanceolate or ovate; smooth; not becoming indurated; entire; awnless to mucronate (acute or apiculate); non-carinate. Palea present; relatively long to conspicuous but relatively short (shorter than the lowest lemma); not convolute; awnless, without apical setae; several nerved. Lodicules present; 3; membranous; ciliate, or glabrous. Stamens 6; with free filaments. Anthers not penicillate; without an apically prolonged connective. Ovary umbonate, apically hairy; with a conspicuous apical appendage. The appendage broadly conical, fleshy. Stigmas 3.

Classification. Watson & Dallwitz (1994): genus not recognised. Soreng et al. (2015): Bambusoideae; Bambusodae; Bambuseae; Bambusinae. 2 species (H. corbuensis, H. pubescens).

Distribution, phytogeography, ecology. Malesia.

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

Special comments. Flowering material of H. pubescens not known. Fruit data wanting. Anatomical data wanting.

Illustrations. • Holttumochloa majica, as Bambusa nana: Gamble, Ann. Royal Bot. Gard. Calcutta 7 (1896).

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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