Dinochloa Buese
From the Greek deinos (fearful, marvellous) and chloa (a grass), alluding to size.
Habit, vegetative morphology. Perennial. The flowering culms leafy. Culms 1000–3000 cm high (sympodial, zigzag); woody and persistent; to 5 cm in diameter; scandent (high-climbing); branched above. Primary branches/mid-culm node several to many. Culm sheaths persistent (with a rugose girdle at the base). Culm internodes solid, or hollow (flexuous). Plants conspicuously armed (thorny), or unarmed (but the culms rough). Leaves not basally aggregated; auriculate (with bristles adjoining). Leaf blades broad; 25–100 mm wide (by 8 to 45 cm long); not cordate, not sagittate (bases cuneate); pseudopetiolate; cross veined; disarticulating from the sheaths; rolled in bud; a fringed membrane (‘shortly ciliate’).
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence indeterminate; with pseudospikelets; a large fan of slender, leafless inflorescence branches up to 3 m long, with spikelets in pairs and groups at their nodes; spatheate; a complex of ‘partial inflorescences’ and intervening foliar organs (but without foliage leaves). Spikelet-bearing axes paniculate; persistent. Spikelets not secund (the spikelet pairs and clusters alternate); pedicellate; consistently in ‘long-and-short’ combinations, or not in distinct ‘long-and-short’ combinations. The ‘shorter’ spikelets hermaphrodite. The ‘longer’ spikelets hermaphrodite.
Female-fertile spikelets. Spikelets 2–4(–5) mm long; slightly compressed laterally; falling with the glumes. Rachilla terminated by a female-fertile floret.
Glumes two, or several (2–3); very unequal (G1 smaller); shorter than the adjacent lemmas; free; conspicuously ventricose; not pointed (broad, obtuse, convolute); awnless; similar. Lower glume 9 nerved (in material seen). Upper glume 9 nerved (in material seen). Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas similar in texture to the glumes; mucronate (or mucronulate); 9 nerved (in the species seen). Palea present (glabrous); relatively long (longer than lemma); apically notched (slightly 2-pointed, the points touching); awnless, without apical setae (mucronate); thinner than the lemma; not indurated; several nerved (11 in the species seen); keel-less. Lodicules absent. Stamens 6 (short). Anthers 4 mm long; penicillate, or not penicillate; with the connective apically prolonged (acute). Ovary glabrous; with a conspicuous apical appendage. The appendage broadly conical, fleshy. Styles fused (into a single style with a wide solid base). Stigmas 3 (slightly plumose).
Fruit, embryo and seedling. Fruit subglobose (spheroidal); not noticeably compressed. Pericarp thin, or fleshy (i.e. pericarp sometimes thick, wrinkled when dry). Embryo large (1/2 to 1/3 as long as fruit). Seed ‘non-endospermic’.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present; intercostal. Intercostal papillae over-arching the stomata; several per cell (variously shaped, sometimes exclusively forming rings over and around the stomata). Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls (thin). Microhairs present; clearly two-celled, or uniseriate (occasionally 3-celled); panicoid-type (rather variable in form); (60–)66–75(–78) microns long (in D. pubivanea); 5.4–19.5 microns wide at the septum. Microhair total length/width at septum 6.7–14.4 (i.e. very variable, in D. pubivanea). Microhair apical cells (31.5–)40.5–42(–51) microns long. Microhair apical cell/total length ratio 0.53–0.65. Stomata common (obscured by papillae); 28.5–30 microns long (in D. pubivanea). Subsidiaries non-papillate. Guard-cells overlapped by the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies tall-and-narrow. Costal short-cells conspicuously in long rows, or predominantly paired, or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies saddle shaped, or tall-and-narrow, or crescentic, or oryzoid.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; with adaxial palisade; with arm cells; with fusoids (very large). The fusoids external to the PBS. Leaf blade adaxially flat. 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’ (most bundles).
Cytology. Chromosome base number, x = 12. 2n = 72.
Taxonomy. Bambusoideae; Bambusodae; Bambuseae.
Distribution, ecology, phytogeography. About 25 species; Southeast Asia, Indo-Malaya.
Paleotropical. Indomalesian. Indo-Chinese and Malesian.
References, etc. Leaf anatomical: Metcalfe 1960; this project.
Cite this publication as: Watson, L., and Dallwitz, M. J. (1992 onwards). ‘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.’ http://biodiversity.uno.edu/delta/. Version: 18th August 1999. Dallwitz (1980), Dallwitz, Paine and Zurcher (1993 onwards, 1998), and Watson and Dallwitz (1994), and Watson, Dallwitz, and Johnston (1986) should also be cited (see References).