Austrochloris Lazarides
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; 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. • Abaxial epidermis of leaf blade. Austrochloris dichanthoides.
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).
