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The grass genera of the world

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

Schizostachyum Nees

From the Greek schistos (cleft) and stachys (‘ear of corn’, spike), referring to spacing of spikelets.

Including Leptocanna Chia & Fung

Excluding Cephalostachyum, Dendrochloa, Pseudostachyum, Teinostachyum

Habit, vegetative morphology. Perennial (the young culm internodes uniformly covered with adpressed white hairs). The flowering culms leafy. Culms 400–1200 cm high; woody and persistent; to 20 cm in diameter; scandent, or not scandent; branched above. Buds from which the primary culm branches arise (very infrequently recorded) 1. Primary branches 4–20 (nearly always many); often clumped. The branching dendroid. Culm leaf sheaths present; deciduous, or persistent; conspicuously auriculate, or not conspicuously auriculate. Culm leaves with conspicuous blades. Culm leaf blades linear, or lanceolate, or triangular. Culm internodes solid, or hollow. Rhizomes pachymorph. Plants unarmed. Young shoots extravaginal. Leaves not basally aggregated; auriculate (the auricles sometimes small, often bristly); with auricular setae (curved). Sheath margins free. Leaf blades broad; 15–90 mm wide (15–50 cm long); pseudopetiolate; cross veined (and often with pellucid dots or dashes), or without cross venation; where recorded, disarticulating from the sheaths. Ligule an unfringed membrane, or a fringed membrane. Contra-ligule present, or absent (mostly).

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

Inflorescence. Inflorescence indeterminate; with pseudospikelets; a false spike, with spikelets on contracted axes, or paniculate (with alternate clusters of pseudospikelets in terminal spike-like or paniculate inflorescences, which are leafless or leafy below); spatheate; a complex of ‘partial inflorescences’ and intervening foliar organs. Spikelet-bearing axes spikelike, or paniculate; persistent. Spikelets not secund.

Female-fertile spikelets. Spikelets unconventional; 12–50 mm long; where recorded, lanceolate (mostly), or linear (rarely, e.g. S. glaucifoilium); compressed laterally to not noticeably compressed (subterete); disarticulating above the glumes; disarticulating between the florets. Rachilla usually prolonged beyond the uppermost female-fertile floret (with a rudimentary floret); the rachilla extension with incomplete florets.

Glumes present, or absent (depending on interpretation); if considered present, one per spikelet to several (3 or 4 ‘bracts’ with buds, in lieu of glumes). Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped. Spikelets without proximal incomplete florets.

Female-fertile florets 1, or 3, or 4. Lemmas similar in texture to the glumes; awned (shortly spine-tipped), or awnless to mucronate (apiculate, with overlapping and convoluted margins). Awns when present, 1; apical; much shorter than the body of the lemma (to 3 mm long). Lemmas non-carinate; 11–17 nerved (in material seen). Palea present; relatively long (usually exceeding the lemma); convolute around the flower, or not convolute; apically notched; shortly 2-pointed; several nerved (11–15 in material seen); 2-keeled (grooved between them, to accommodate the rachilla). Lodicules present, or absent (sometimes exhibiting transitions between stamens and lodicules); when present, 1–10; free; membranous; ciliate. Stamens usually 6; with free filaments (usually), or monadelphous (rarely), or monadelphous to triadelphous (with groups recorded in a few species). Anthers 5–14 mm long; penicillate, or not penicillate; with the connective apically prolonged, or without an apically prolonged connective. Ovary apically glabrous; with a conspicuous apical appendage. The appendage long, stiff and tapering. Styles fused (the single style hollow). Stigmas 3 (simple); white, or red pigmented.

Fruit, embryo and seedling. Fruit compressed laterally. Hilum long-linear. Pericarp thick and hard (leathery to crustaceous); free. Embryo small.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present (costally and intercostally). Intercostal papillae over-arching the stomata (and completely obscuring them); several per cell (large, one row per long-cell). Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally (walls of medium thickness). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type; (54–)57–63(–69) microns long; (8.4–)9 microns wide at the septum. Microhair total length/width at septum 6–7.7. Microhair apical cells (28–)30–36(–39) microns long. Microhair apical cell/total length ratio 0.53–0.57. Stomata common (outlines obscured by papillae); 19.5–21–24 microns long. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies tall-and-narrow. Crown cells present (at least, having large umbonate or tiny-pointed ‘prickles’). Costal short-cells predominantly paired. Costal silica bodies rounded, or saddle shaped, or tall-and-narrow, or crescentic, or oryzoid (predominantly tall-and-narrow, overlapping into ovals, crescents and near-oryzoids); not sharp-pointed.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with adaxial palisade; with arm cells; with fusoids. The fusoids external to the PBS. Leaf blade adaxially flat (save alongside the midrib). Midrib conspicuous; having complex vascularization. Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’ (the larger bundles). Sclerenchyma all associated with vascular bundles.

Special diagnostic feature. The inflorescences not as in Atractantha (q.v.).

Classification. Watson & Dallwitz (1994): Bambusoideae; Bambusodae; Bambuseae. Soreng et al. (2015): Bambusoideae; Bambusodae; Bambuseae; Melocanninae. 35 species.

Distribution, phytogeography, ecology. Eastern Asia.

Halophytic (S. pulchellum), or glycophytic. Mostly savanna, rarely coastal sand.

Economic aspects. Pliant, tough splints of S. dumetorum constitute thonging, and the whole culms are pounded and twisted into ropes. S. jaculans is the blowpipe bamboo of lowland Malaya.

References, etc. Leaf anatomical: Metcalfe 1960; studied by us - Schizostachyum lima Merril.

Illustrations. • S. dullooa and S. griffithii (as Teinostachyum spp., with Davidsea attenuata): Camus, 1913.. • Abbreviations for Camus (1913) figures. • S. aciculare, S. iraten, S. zollingeri (Camus, 1913). • S.blumei, S. lima (as hallieri): Camus, 1913.. • S. dulloa (as Neohouzeaua, with N. mekongensis: E.G. Camus & M.A. Camus (1922), Fl. Gen. d'Indo-Chine.. • S. lima, abaxial epidermis of leaf blade: this project

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: 11th December 2017.’.