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The grass genera of the world

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

Anomochloa Brongn.

Habit, vegetative morphology. Perennial; rhizomatous and caespitose. Culms 30–50 cm high; herbaceous; unbranched above. Culm internodes solid. Rhizomes pachymorph. Leaves mostly basal; auriculate (on the sheaths); without auricular setae. Leaf blades narrowly lanceolate (to oblong-lanceolate); broad; (40–)60–100 mm wide (18–40 cm long); cordate; flat; pseudopetiolate (the ‘petioles’ up to 25 cm); palmately veined; cross veined; seemingly persistent (but more or less ‘articulated’); rolled in bud. Ligule a fringe of hairs. Contra-ligule absent.

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

Inflorescence. Inflorescence spicate, cymoid, with 2–5 spikelets in the axil of each bract; spatheate (and spatheolate); a complex of ‘partial inflorescences’ and intervening foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; secund (in the partial inflorescences); pedicellate.

Female-fertile spikelets. Spikelets unconventional (apparently lacking glumes, exhibiting an upper and a lower ‘bract’ and a ‘perigonate annulus’, all presenting interpretive problems). Rachilla terminated by a female-fertile floret.

Glumes absent. Spikelets with female-fertile florets only.

Female-fertile florets 1. Lemmas (if the lower ‘bract’ is seen as such) leathery, ovate, tessellate-nerved; not becoming indurated; non-carinate; without a germination flap; many nerved. Palea (if the ‘upper bract’ be so interpreted) present; forming a closed tube below, enclosing the flower; several nerved; keel-less. Lodicules present; joined (confluent, in the form of an annulus - if the annulus be so interpreted); ciliate (in that the annulus is fringed). Stamens 4. Anthers 3–5 mm long. Ovary apically glabrous. Stigmas 1.

Fruit, embryo and seedling. Fruit medium sized (up to 10 mm long); oblong to rectangular; shallowly longitudinally grooved; compressed laterally. Hilum long-linear. Embryo large (nearly as long as the fruit). Endosperm containing compound starch grains. Embryo with an epiblast; with a scutellar tail (inconspicuous); with a negligible mesocotyl internode. Embryonic leaf margins meeting.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Intercostal zones exhibiting many atypical long-cells (rather short). Mid-intercostal long-cells having markedly sinuous walls. Microhairs present; more or less spherical to elongated; clearly two-celled; panicoid-type; (74–)80–90(–115) microns long. Microhair apical cells (45–)48–60(–63) microns long. Microhair apical cell/total length ratio about 0.64. Stomata common. Subsidiaries low dome-shaped and triangular. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies tall-and-narrow. Costal short-cells neither distinctly grouped into long rows nor predominantly paired (in series of 2–4). Costal silica bodies horizontally-elongated smooth and rounded.

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; with arm cells; with fusoids. The fusoids external to the PBS. Leaf blade blade with slight ribs and furrows adaxially. Midrib conspicuous (projecting adaxial rib); having complex vascularization (a large abaxial bundle, and 2 smaller ones in a line above it). Bulliforms present in discrete, regular adaxial groups to not present in discrete, regular adaxial groups; in groups of the ‘irregular’ type. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming ‘figures’ (incomplete anchors). Sclerenchyma all associated with vascular bundles.

Special diagnostic feature. Inflorescence of 2–3 glumeless, bracteate spikelets, the lodicules represented by a fringed annulus.

Cytology. Chromosome base number, x = 9. 2n = 36.

Classification. Watson & Dallwitz (1994): Bambusoideae; Oryzodae; Anomochloeae. Soreng et al. (2015): Anomochlooideae; Anomochloeae. 1 species.

Distribution, phytogeography, ecology. Tropical America.

Shade species. In forests.

References, etc. Morphological/taxonomic: Judziewcz and Soderstrom 1989. Leaf anatomical: Metcalfe 1960, Judziewcz and Soderstrom 1989.

Illustrations. • A. marantoidea (Fl. Bras. 2(2), 1871)


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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: 13th November 2017. delta-intkey.com/grass’.

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