The grass genera of the world
From Latin australis (south), and Chloris (the grass genus in which it was formerly included).
Habit, vegetative morphology. Perennial; caespitose. Culms 40–100 cm high; herbaceous. Culm nodes glabrous. Culm internodes solid. Leaves not basally aggregated; non-auriculate. Leaf blades narrow; 2–3 mm wide; without abaxial multicellular glands; without cross venation; persistent. Ligule a fringed membrane.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence of spicate main branches; digitate. Primary inflorescence branches 2, or 3. Rachides hollowed, or flattened (triquetrous). Inflorescence espatheate; not comprising partial inflorescences and foliar organs. Spikelet-bearing axes persistent. Spikelets solitary; secund; biseriate.
Female-fertile spikelets. Spikelets compressed dorsiventrally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret; hairy; the rachilla extension with incomplete florets. Hairy callus absent.
Glumes two; more or less equal; exceeding the spikelets; long relative to the adjacent lemmas; pointed (acuminate); awnless; carinate; similar (narrow, membranous, divergent, the upper deciduous). Lower glume 1 nerved. Upper glume 3 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets 1 (neuter, with a cuneate lemma). Spikelets without proximal incomplete florets.
Female-fertile florets 1. Lemmas broadly rounded; decidedly firmer than the glumes (cartilaginous); entire, or incised; when entire pointed, or blunt; awned. Awns 1; median; dorsal; from near the top; non-geniculate; about as long as the body of the lemma. Lemmas hairy; non-carinate (with 3 hairy keels); 3 nerved. Palea present; entire; awnless, without apical setae; thinner than the lemma (scarious); not indurated; 2-nerved. Lodicules present; 2; free; fleshy; glabrous. Stamens 3. Anthers 0.5 mm long; not penicillate. Ovary glabrous. Styles free to their bases. Stigmas 2; red pigmented.
Fruit, embryo and seedling. Fruit small; ellipsoid; compressed dorsiventrally. Hilum short. Pericarp free. Embryo large.
Abaxial leaf blade epidermis. Papillae present; intercostal. Intercostal papillae not over-arching the stomata; consisting of one oblique swelling per cell. Mid-intercostal long-cells having markedly sinuous walls. Microhairs present; more or less spherical; clearly two-celled; chloridoid-type. Microhair apical cell wall of similar thickness/rigidity to that of the basal cell. Microhairs 24–27 microns long. Microhair basal cells 12–16 microns long. Microhairs 10.5–12 microns wide at the septum. Microhair total length/width at septum 2–2.4. Microhair apical cells (7.5–)9–11(–12) microns long. Microhair apical cell/total length ratio 0.31–0.47. Stomata common; 18–22.5 microns long. Subsidiaries non-papillate; triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare. Intercostal silica bodies absent. Costal short-cells conspicuously in long rows, or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies present in alternate cell files of the costal zones; saddle shaped.
Transverse section of leaf blade, physiology. Lamina mid-zone in transverse section open.
C4; XyMS+. PCR sheath outlines even. PCR sheaths of the primary vascular bundles interrupted; interrupted abaxially only. PCR sheath extensions absent. PCR cell chloroplasts centripetal. Mesophyll with radiate chlorenchyma. Leaf blade nodular in section; with the ribs more or less constant in size. Midrib conspicuous to not readily distinguishable; with one bundle only, or with one bundle only to having a conventional arc of bundles (?). Bulliforms present in discrete, regular adaxial groups; in simple fans. All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present; forming figures. Sclerenchyma all associated with vascular bundles.
Taxonomy. Chloridoideae; main chloridoid assemblage.
Distribution, ecology, phytogeography. 1 species; Australia. Species of open habitats. Savanna.
Australian. North and East Australian and Central Australian. Tropical North and East Australian.
References, etc. Morphological/taxonomic: Lazarides 1985. Leaf anatomical: this project.
Illustrations. • General aspect and details (Austrochloris dichanthioides). • Abaxial epidermis of leaf blade (A. dichanthioides)
This description is offered for casual browsing only. We strongly advise against extracting comparative information from it. This is much more easily achieved using 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 specified attributes, summaries of attributes within groups of taxa, geographical distribution, classification, and species sampled for anatomy.
Cite this publication as: ‘Watson, L., 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: 18th December 2012. http://delta-intkey.com’.