Clausospicula M. Lazarides
Sometimes referred to Anadelphia sensu lato
Habit, vegetative morphology. Annual. Culms herbaceous; branched above. Leaves not basally aggregated. Leaf blades linear; 1.4–2.6 mm wide; flat, or folded; without cross venation; persistent; ligule present; an unfringed membrane; truncate; 0.3–0.5 mm long. Contra-ligule absent.
Reproductive organization. Plants bisexual, with bisexual spikelets; with hermaphrodite florets. The spikelets of sexually distinct forms on the same plant; hermaphrodite and sterile. The male and female-fertile spikelets mixed in the inflorescence. The spikelets overtly heteromorphic; all in heterogamous combinations. Plants inbreeding; exposed-cleistogamous.
Inflorescence. Inflorescence paniculate; open; spatheate (and spatheolate); a complex of ‘partial inflorescences’ and intervening foliar organs. Spikelet-bearing axes very much reduced (each ‘raceme’ reduced to one ‘triplet’, clasped basally by the peculiar, trumpet-shaped tip of the peduncle); the spikelet-bearing axes with only one spikelet-bearing ‘article’; spikelet-bearing axes solitary; disarticulating; disarticulating at the joints (i.e. each at its only joint). The pedicels and rachis internodes without a longitudinal, translucent furrow. ‘Articles’ without a basal callus-knob; disarticulating obliquely. Spikelets in triplets (one of the pedicellate members sometimes missing); sessile and pedicellate; consistently in ‘long-and-short’ combinations; in pedicellate/sessile combinations. Pedicels of the ‘pedicellate’ spikelets free of the rachis. The ‘shorter’ spikelets hermaphrodite. The ‘longer’ spikelets sterile (sometimes reduced to the glabrous pedicels).
Female-sterile spikelets. The sterile spikelets, when present, 5–12 mm long, linear to lanceolate, awnless, disarticulating horizontally.
Female-fertile spikelets. Spikelets about 10 mm long; not noticeably compressed to compressed dorsiventrally; falling with the glumes. Rachilla terminated by a female-fertile floret. Hairy callus present. Callus long; pointed.
Glumes present; two; more or less equal; about equalling the spikelets, or exceeding the spikelets; long relative to the adjacent lemmas (more or less exceeding the L1); hairy and hairless (usually tubercled basally and towards the tip, otherwise glabrous); without conspicuous tufts or rows of hairs; awned; non-carinate; very dissimilar (both becoming indurated, the lower abruptly contracted above and with or without a short bristle from the narrow, truncate to notched apex, the upper attenuate into a long, slender scabrous awn 14–19 mm long which is often twisted around the lemma awn). Lower glume not two-keeled; convex on the back; not pitted; relatively smooth and tuberculate; 4 nerved (without a median). Upper glume 3 nerved. Spikelets with incomplete florets. The incomplete florets proximal to the female-fertile florets. Spikelets with proximal incomplete florets. The proximal incomplete florets 1; epaleate; sterile. The proximal lemmas awnless; 2 nerved, or 4 nerved; more or less equalling the female-fertile lemmas to decidedly exceeding the female-fertile lemmas; similar in texture to the female-fertile lemmas (hyaline); not becoming indurated.
Female-fertile florets 1. Lemmas less firm than the glumes; not becoming indurated; entire (the hyaline margins of the stipe antero-laterally decurrent on the base of the awn, with no indication of lobes); awned. Awns 1; median; apical; geniculate; hairless to hairy; much longer than the body of the lemma (8–11 cm long); entered by several veins. Awn bases twisted; not flattened. Lemmas hairless; glabrous; non-carinate; without a germination flap; 3 nerved; with the nerves non-confluent. Palea present; conspicuous but relatively short; entire to apically notched; awnless, without apical setae; textured like the lemma (hyaline); not indurated; 2-nerved, or nerveless. Lodicules present; 2; free; fleshy; glabrous. Stamens 3 (short). Anthers 0.5–1.5 mm long; not penicillate; without an apically prolonged connective. Ovary glabrous. Styles free to their bases. Stigmas 2, or 3.
Fruit, embryo and seedling. Fruit free from both lemma and palea; medium sized (about 5.6 mm long); ellipsoid; compressed laterally (above), or compressed dorsiventrally to not noticeably compressed (below); glabrous. Hilum short. Embryo large.
Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular to fusiform; having markedly sinuous walls. Microhairs present; panicoid-type; 39–47 microns long; 6–12 microns wide at the septum. Microhair total length/width at septum 3.25–7.5. Microhair apical cells 22–30 microns long. Microhair apical cell/total length ratio 0.57–0.67. Stomata common; 31–41 microns long. Subsidiaries triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs; silicified. Intercostal silica bodies cross-shaped. Costal zones with short-cells. Costal short-cells conspicuously in long rows, or predominantly paired, or neither distinctly grouped into long rows nor predominantly paired. Costal silica bodies ‘panicoid-type’; not sharp-pointed.
Transverse section of leaf blade, physiology. C4; XyMS–. PCR sheath outlines uneven. PCR sheath extensions absent. Leaf blade with distinct, prominent adaxial ribs (the ribs low, variable in width). Midrib conspicuous; having a conventional arc of bundles (a large median, with four or five laterals on either side in a deep arc); with colourless mesophyll adaxially. Bulliforms present in discrete, regular adaxial groups (in places), or not present in discrete, regular adaxial groups (mainly, the epidermis largely bulliform); in simple fans (in places), or associated with colourless mesophyll cells to form deeply-penetrating fans (mainly); associating with colourless mesophyll cells to form arches over small vascular bundles (noticeable only in Barritt 772), or nowhere involved in bulliform-plus-colourless mesophyll arches. Many of the smallest vascular bundles unaccompanied by sclerenchyma. Combined sclerenchyma girders present; nowhere forming ‘figures’. Sclerenchyma all associated with vascular bundles.
Special diagnostic feature. Spikelets in much-reduced andropogonoid ‘racemes’, each of the latter reduced to a single triplet and enclosed at its base by a trumpet-like development of the peduncle tip.
Taxonomy. Panicoideae; Andropogonodae; Andropogoneae; Andropogoninae.
Distribution, ecology, phytogeography. 1 species; northern Australia.
Australian. North and East Australian.
References, etc. Morphological/taxonomic: Lazarides et al. 1990. 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).