Asthenochloa Buese
Including Garnotiella Stapf
Habit, vegetative morphology. Decumbent annual, or perennial. Culms herbaceous (slender); branched above. Leaves not basally aggregated. Leaf blades linear-lanceolate to lanceolate; narrow; without cross venation.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant (but obscurely so, the ‘pedicellate spikelet’ being reduced to a minute pedicel hidden in the callus hairs); hermaphrodite, or hermaphrodite and sterile (but the latter rudimentary).
Inflorescence. Inflorescence paniculate (decompound); open; spatheate; a complex of ‘partial inflorescences’ and intervening foliar organs. Spikelet-bearing axes very much reduced (pedicel-like, with cupuliform, long-hairy apices, bearing a plexus of a minute stipe (= rudiment of pedicelled spikelet), and one sessile spikelet); solitary; disarticulating; disarticulating at the joints (i.e., the spikelet and its vestigial companion (plus the bearded callus) articulate with the apex of the pedicel-like branchlet). ‘Articles’ with a basal callus-knob; densely long-hairy. Spikelets paired (but the pedicellate member suppressed); sessile and pedicellate (the latter reduced to their pedicels); consistently in ‘long-and-short’ combinations. Pedicels of the ‘pedicellate’ spikelets free of the rachis (but small and inconspicuous). The ‘shorter’ spikelets hermaphrodite. The ‘longer’ spikelets sterile (reduced to tiny pedicels).
Female-fertile spikelets. Spikelets 2–2.5 mm long; compressed dorsiventrally (?); falling with the glumes. Rachilla terminated by a female-fertile floret. Hairy callus present (the hairs up to two thirds as long as spikelet).
Glumes two; more or less equal (G2 somewhat longer); long relative to the adjacent lemmas; glumes with ciliate margins; awned (sometimes, G2), or awnless; carinate (G2), or non-carinate (G1); very dissimilar (thinly herbaceous; G1 2-toothed, dorsally flattened; G2 acuminate or short-awned, naviculate). Lower glume flattened on the back; not pitted; relatively smooth; 2 nerved. Upper glume 3 nerved. Spikelets with female-fertile florets only; without proximal incomplete florets.
Female-fertile florets 1. Lemmas less firm than the glumes (thinly membranous); not becoming indurated; incised; awned. Awns 1; median; from a sinus; geniculate; hairless (scabrid); much longer than the body of the lemma. Lemmas hairless (the lobes shortly ciliolate); non-carinate; 1 nerved (?). Palea absent. Lodicules absent. Stamens 2. Anthers not penicillate; without an apically prolonged connective. Ovary glabrous. Stigmas 2.
Fruit, embryo and seedling. Hilum short. Embryo large.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present; costal and intercostal. Intercostal papillae not over-arching the stomata; several per cell (one median row of papillae per long-cell). Long-cells markedly different in shape costally and intercostally (the costals narrower). Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; elongated; clearly two-celled; panicoid-type; 39–51 microns long; 6–7.5 microns wide at the septum. Microhair total length/width at septum 6–7.5. Microhair apical cells 16–21 microns long. Microhair apical cell/total length ratio 0.33–0.43. Stomata common. Subsidiaries dome-shaped. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare. Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’.
Transverse section of leaf blade, physiology. Probably C4 (the material seen very poor). Midrib conspicuous; with one bundle only; with colourless mesophyll adaxially.
Taxonomy. Panicoideae; Andropogonodae; Andropogoneae; Andropogoninae.
Distribution, ecology, phytogeography. 1 species; Indonesian Archipelago. Mesophytic. In damp places.
Paleotropical. Indomalesian. Malesian.
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).