| # The grass genera of the world |

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

### Chimonocalamus (Hsueh & T. P. Yi) C. S. Chao & Renvoize

~ Variously Arundinaria, Chimonobambusa, Sinarundinaria, Sinarundinaria Nakai sect. Chimonocalamus, Semiarundinaria

Habit, vegetative morphology. Shrubby or arborescent perennial. Culms 150–1000 cm high; woody and persistent (the lower nodes often with thornlike roots); usually cylindrical (rarely quadrangular); branched above. Buds from which the primary culm branches arise (where recorded) 1. Primary branches 3–20; horizontally aligned, or in an irregular line. The branching dendroid. Culm nodes swollen, with a slight supra-nodal ridge. Culm leaf sheaths present; at least usually deciduous; conspicuously auriculate, or not conspicuously auriculate. Culm leaves with conspicuous blades. Culm leaf blades linear, or lanceolate, or ovate, or triangular. Rhizomes short-necked pachymorph. Leaves auriculate (rarely), or non-auriculate; without auricular setae. Leaf blades usually small, linear, or linear-lanceolate, or lanceolate, or elliptic; pseudopetiolate; herbaceous or chartaceous, cross veined to without cross venation; disarticulating from the sheaths, or persistent. Ligule an unfringed membrane (usually), or a fringed membrane (rarely). Contra-ligule absent.

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

Inflorescence. Inflorescence determinate; without pseudospikelets; paniculate (terminating leafy branches); open; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelets solitary; long pedicellate.

Female-fertile spikelets. Spikelets 8–80 mm long; linear (nearly always), or oblong to lanceolate (C. baviensis); compressed laterally; disarticulating above the glumes; disarticulating between the florets. Rachilla prolonged beyond the uppermost female-fertile floret; hairy (distinct, with pubescent or pilose internodes); the rachilla extension with incomplete florets.

Glumes two; shorter than the spikelets; glabrous or puberulous, not pitted; pointed; muticous or mucronate, awnless; carinate, or non-carinate; chartaceous. Lower glume 3–9 nerved. Upper glume 5–7 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 2–10. Lemmas lanceolate or ovate; chartaceous, similar in texture to the glumes to decidedly firmer than the glumes; smooth; not becoming indurated; entire; pointed (acute, acuminate or setaceously acuminate); mucronate; hairy, or hairless; non-carinate; 5–9 nerved. Palea present; relatively long (about equalling the to exceeding lemma); entire, or apically notched (muticous, dentate, or with excurrent keel veins); awnless, without apical setae, or with apical setae; 2-keeled. Palea keels ciliolate or glabrous. Lodicules present; 3. Third lodicule present. Lodicules membranous; ciliate, or glabrous. Stamens 3; with free filaments. Ovary apically glabrous; without a conspicuous apical appendage. Stigmas 2–3.

Fruit, embryo and seedling. Fruit slender, beaked. Pericarp fused.

Special diagnostic feature. Not rush-like.

Classification. Watson & Dallwitz (1994): genus not recognised. Soreng et al. (2015): Bambusoideae; Arundinarodae; Arundinarieae; Arundinariinae. About 12 species.

Distribution, phytogeography, ecology. Temperate to tropical Asia - eastern Himalayas, Burma, SW China (nine species (eight endemic) in China.

Economic aspects. Most species in this genus produce delicious bamboo shoots and are known as "xiang zhu" (??), meaning "fragrant bamboo." The robust culms are widely used in Yunnan for construction and agricultural tools. Chimonocalamus pallens and C. dumosus are attractive, subtropical ornamentals and have been introduced into gardens.

References, etc. Morphological/taxonomic: Clayton et al. (2016), Grassbase; Flora of China vol 22.

Special comments. Anatomical data wanting.

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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