| # The grass genera of the world |

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

### Drepanostachyum Keng f.

~ Sinarundinaria

Type species: D. falcatum Keng f.

Habit, vegetative morphology. Perennial. Culms erect, 140–540 cm high; woody and persistent (without nodal roots); cylindrical (with swollen nodes); branched above. Primary branches 3–20 (to many); thinner than the stem, subequal, horizontally aligned, or in an irregular line, or clumped. The branching dendroid. Culm leaves present, or absent (sometimes leafless when inflorescence-bearing). Culm leaf sheaths present; deciduous to persistent; leaving a persisten girdle, or not leaving a persistent girdle; not conspicuously auriculate. Culm leaves with conspicuous blades. Culm leaf blades linear, or linear to lanceolate. Rhizomes pachymorph. Leaves auriculate (falcate), or non-auriculate; without auricular setae. Leaf blades herbaceous or chartaceous, linear, or linear-lanceolate, or lanceolate, or elliptic; pseudopetiolate; more or less obscurely cross veined to without cross venation; disarticulating from the sheaths, or persistent. Ligule an unfringed membrane to a fringed membrane.

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

Inflorescence. Inflorescence determinate; without pseudospikelets; terminal, or terminal and axillary, of spicate main branches, or paniculate; open, or contracted; subtended by a bract or an unspecialized sheath; not comprising ‘partial inflorescences’ and foliar organs. Spikelets solitary; not secund; pedicellate.

Female-fertile spikelets. Spikelets 8–25 mm long; linear, or oblong, or lanceolate, or ovate; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with distinctly elongated rachilla internodes between the florets (internodes "definite"). Rachilla prolonged beyond the uppermost female-fertile floret; hairy to hairless; the rachilla extension with incomplete florets (usually), or naked.

Glumes two; very unequal; shorter than the spikelets to about equalling the spikelets (somewhat shorter); shorter than the adjacent lemmas; hairless; glabrous, or scabrous; pointed to not pointed (obtuse, acute or acuminate); muticous or mucronate, awnless; carinate, or non-carinate (usually); persistent, herbaceous or chartaceous, lanceolate, ovate or elliptic, similar. Lower glume about 0.8 times the length of the upper glume; 3–7 nerved. Upper glume 5–9 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped (usually), or clearly specialised and modified in form. Spikelets without proximal incomplete florets.

Female-fertile florets (1–)2–12. Lemmas ovate; herbaceous or chartaceous, similar in texture to the glumes; with prominent lateral veins, smooth; not becoming indurated; entire; pointed; acute or acuminate, awnless, or mucronate; hairy, or hairless; non-carinate; 7–9 nerved. Palea present; relatively long (about equalling the lemma); entire, or apically notched; awnless, without apical setae to with apical setae (sometimes with excurrent keel veins); 2-nerved, or several nerved (2–6); 2-keeled. Palea keels glabrous, or scabrous. Lodicules present; 3. Third lodicule present. Lodicules membranous; ciliate, or glabrous. Stamens 3. Ovary apically glabrous; without a conspicuous apical appendage. Stigmas 2.

Fruit, embryo and seedling. Fruit not apically appendaged, fusiform; not grooved. Hilum long-linear. Pericarp fused.

Special diagnostic feature. Not rush-like.

Classification. Watson & Dallwitz (1994): genus not recognised. Soreng et al. (2015): Bambusoideae; Arundinarodae; Arundinarieae; Arundinariinae. About 13 species.

Distribution, phytogeography, ecology. Temperate and tropical Asia.

Special comments. Anatomical data wanting.

Illustrations. • Drepanostachyum polystachyum (as Arundinaria: 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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