Micraira F. Muell.
Habit, vegetative morphology. Mat-forming perennial (polytrichoid in appearance). Culms 1–9 cm high; herbaceous. Leaves not basally aggregated; spirally disposed; non-auriculate. Leaf blades narrow; cordate, or not cordate, not sagittate; setaceous to not setaceous (pungent or muticous); pseudopetiolate, or not pseudopetiolate; without cross venation; disarticulating from the sheaths; a fringed membrane to a fringe of hairs.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets.
Inflorescence. Inflorescence a single spike, or a single raceme, or paniculate; open, or contracted; with capillary branchlets; espatheate; not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets not secund; pedicellate; not in distinct ‘long-and-short’ combinations.
Female-fertile spikelets. Spikelets 0.75–2 mm long; compressed laterally; disarticulating above the glumes. Rachilla prolonged beyond the uppermost female-fertile floret. Hairy callus absent.
Glumes two; more or less equal; shorter than the spikelets to exceeding the spikelets; shorter than the adjacent lemmas to long relative to the adjacent lemmas; pointed; awnless (muticous, mucronate or mucronulate); similar (membranous). Lower glume 1 nerved. Upper glume 1 nerved. Spikelets with female-fertile florets only, or with incomplete florets. The incomplete florets proximal to the female-fertile florets. The proximal incomplete florets 1; male, or sterile. The proximal lemmas awnless; 5–9 nerved; more or less equalling the female-fertile lemmas; similar in texture to the female-fertile lemmas; not becoming indurated.
Female-fertile florets 1–2. Lemmas almost rectangular; less firm than the glumes (thinly membranous to hyaline); not becoming indurated; entire; blunt; awnless; hairless; carinate to non-carinate; 5–9 nerved. Palea present; relatively long, or conspicuous but relatively short, or very reduced (almost rectangular); entire to deeply bifid; awnless, without apical setae; thinner than the lemma to textured like the lemma; not indurated; 2-nerved, or several nerved (2, or 5–7); 2-keeled. Lodicules absent. Stamens 2. Anthers 0.5–1.2 mm long; not penicillate. Ovary glabrous. Stigmas 2; red pigmented.
Fruit, embryo and seedling. Fruit small (0.3–0.75 mm long); ellipsoid; compressed dorsiventrally. Hilum long-linear. Embryo small. Endosperm containing only simple starch grains. Embryo without an epiblast; with a scutellar tail.
First seedling leaf with a well-developed lamina. The lamina narrow; curved.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae present, or absent (e.g., M. subulifolia). Intercostal papillae not over-arching the stomata; several per cell (small, up to 15 per cell). Long-cells similar in shape costally and intercostally (but the costals rather smaller); of similar wall thickness costally and intercostally (thin walled). Mid-intercostal long-cells rectangular; having markedly sinuous walls, or having straight or only gently undulating walls. Microhairs present; panicoid-type; (36–)45–51 microns long; 3.6–6.5(–8.4) microns wide at the septum. Microhair total length/width at septum 6.1–13.3. Microhair apical cells (16.5–)22.5–24(–25.5) microns long. Microhair apical cell/total length ratio 0.46–0.55. Stomata absent or very rare, or common; 18–24 microns long. Subsidiaries dome-shaped. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells absent or very rare; not paired (rare); not silicified. Costal short-cells conspicuously in long rows. Costal silica bodies ‘panicoid-type’; short, angular, butterfly shaped, or dumb-bell shaped, or cross shaped; sharp-pointed (all the silica-bodies angular, many more or less rectangular - cf. Pheidochloa, but not vertically elongated).
Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; Isachne-type, or not Isachne-type (e.g., M. subulifolia). Leaf blade with the ribs more or less constant in size. Midrib not readily distinguishable; with one bundle only. 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. Arundinoideae; Micraireae.
Distribution, ecology, phytogeography. 13 species; Australia. Rocky places, in shallow soils.
Australian. North and East Australian. Tropical North and East Australian.
References, etc. Morphological/taxonomic: Clifford 1964; Lazarides 1979, 1985. Leaf anatomical: Metcalfe 1960; this project.
Illustrations. • General morphology. • General morphology. • Spiral phyllotaxy. Micraira subspicata. • Leafy shoot. Micraira sp. Spiral phyllotaxy, leaf blades disarticulated from sheaths (below). • General aspect
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).
