Diandrolyra Stapf
Habit, vegetative morphology. Perennial; caespitose. The flowering culms leafy (but tending to carry the racemes on specialised, 1-leafed culms). Culms about 10–50 cm high; herbaceous; unbranched above. Culm nodes glabrous. Culm internodes solid. Plants unarmed. Young shoots extravaginal, or intravaginal. Leaves not basally aggregated; non-auriculate. Leaf blades broad; pseudopetiolate; cross veined; persistent; rolled in bud; a fringed membrane; 0.5–1.2 mm long.
Reproductive organization. Plants monoecious with all the fertile spikelets unisexual; without hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; female-only and male-only. The male and female-fertile spikelets mixed in the inflorescence (paired, male and female). The spikelets overtly heteromorphic. Not viviparous.
Inflorescence. Inflorescence a short raceme, terminal on a normal leafy or a special 1-leafed culm, borne horizontally beneath the blade of the bent subtending leaf. Spikelet-bearing axes persistent. ‘Articles’ not appendaged; glabrous. Spikelets paired (male and female); not secund; pedicellate; not in distinct ‘long-and-short’ combinations.
Female-sterile spikelets. Male spikelets with glumes reduced or lacking, having 3 stamens plus 3 staminodes and a sterile ovary with three stigmas. The male spikelets without glumes (or these vestigial); without proximal incomplete florets; 1 floreted. The lemmas awnless. Male florets 3 staminate, or 6 staminate (including the 3 staminodes). The staminal filaments free.
Female-fertile spikelets. Spikelets 9–11 mm long; not noticeably compressed; falling with the glumes. Rachilla terminated by a female-fertile floret.
Glumes two; more or less equal; long relative to the adjacent lemmas; hairless; awnless; non-carinate; similar (herbaceous, cuspidate). Lower glume 5–6 nerved. Upper glume 5–7 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas similar in texture to the glumes (leathery); not becoming indurated; entire; blunt; awnless; hairless; glabrous; non-carinate; without a germination flap; 5–8 nerved. Palea present; relatively long; entire; awnless, without apical setae; not indurated; 2-nerved to several nerved; keel-less. Lodicules present; 3; free; fleshy; glabrous; toothed; not or scarcely vascularized. Stamens 0 (three staminodes). Styles fused (style base hairy). Stigmas 2.
Fruit, embryo and seedling. Fruit free from both lemma and palea; medium sized; compressed dorsiventrally. Hilum long-linear. Embryo small; not waisted. Endosperm hard; containing compound starch grains.
Seedling with a short mesocotyl; with a loose coleoptile. First seedling leaf without a lamina (two bladeless sheaths).
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present. Intercostal papillae over-arching the stomata; several per cell. Long-cells markedly different in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type. Stomata common. Subsidiaries triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies vertically elongated-nodular (?). Costal short-cells conspicuously in long rows. Costal silica bodies oryzoid.
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; with arm cells; with fusoids. Leaf blade adaxially flat. Midrib having a conventional arc of bundles. Bulliforms present in discrete, regular adaxial groups; in simple fans (the groups wide). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Cytology. Chromosome base number, x = 11.
Taxonomy. Bambusoideae; Oryzodae; Olyreae.
Distribution, ecology, phytogeography. 1 species; Panama. Shade species. Forest.
Neotropical. Central Brazilian.
References, etc. Leaf anatomical: 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).