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The grass genera of the world

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

Cyperochloa Lazarides & L. Watson

From the Greek chloa (a grass), and alluding to the cyperaceous appearance of the inflorescence.

Type species: Type: C. hirsuta Lazarides & L.Watson.

Habit, vegetative morphology. Wiry perennial (remarkably sedge-like in appearance, the plants forming colonies up to 2 m across); caespitose. Culms 7–50 cm high; herbaceous; unbranched above. Culm nodes erect, terete, glabrous or the topmost node pubescent. Culm internodes solid. Young shoots intravaginal. Leaves mostly basal; non-auriculate (but the ligule continuous with hairs at the lateral tips of the sheath). Leaf blades narrow; recurved, setaceous; tightly rolled; not pseudopetiolate; without cross venation; persistent. Ligule a fringe of hairs (short, dense). Contra-ligule absent.

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

Inflorescence. Inflorescence few spikeleted (generally 2–5); paniculate (borne on a very short peduncle, subtended by a short-sheathed terminal leaf with a reduced blade, atop the single elongated culm internode); contracted; capitate (consisting of 2–5 digitately-borne, bracteate spikelets); spatheate (the inflorescence subtended by the leaflike spathe, and each spikelet by a small, glume-like bract); not comprising ‘partial inflorescences’ and foliar organs. Spikelet-bearing axes persistent. Spikelets sessile to subsessile.

Female-fertile spikelets. Spikelets 7–9 mm long; broadly ovate; compressed laterally; disarticulating above the glumes; disarticulating between the florets; with conventional internode spacings. Rachilla prolonged beyond the uppermost female-fertile floret; hairless (each joint glabrous below the callus); the rachilla extension with incomplete florets. Hairy callus present. Callus short; blunt.

Glumes present; two; very unequal (the G2 generally longer); shorter than the spikelets; shorter than the adjacent lemmas; hairy (hirsute or pubescent below and sometimes on the nerves, the margins ciliate); without conspicuous tufts or rows of hairs; pointed (acute), or not pointed (obtuse or emarginate); awnless (muticous); carinate to non-carinate (slightly keeled to rounded on the back); similar (ovate to lanceolate, membranous to cartilaginous). Lower glume 3 nerved, or 5 nerved. Upper glume 3 nerved, or 5 nerved. Spikelets with incomplete florets. The incomplete florets distal to the female-fertile florets. The distal incomplete florets merely underdeveloped (i.e., the upper 1–2).

Female-fertile florets 4–9. Lemmas similar in texture to the glumes; not becoming indurated; entire, or incised; blunt; not deeply cleft (at the most, minutely cleft); awnless (at the most, with a minute projection from the median nerve); hairy (conspicuously so below and on the margins, and also adaxially near the tip); carinate; without a germination flap; 5 nerved, or 7 nerved. Palea present; relatively long; entire to apically notched (no more than minutely so); awnless, without apical setae; thinner than the lemma (membranous with hyaline margins, hairy); not indurated; 2-nerved; 2-keeled. Palea keels wingless. Lodicules present; 2; free; fleshy; ciliate; not or scarcely vascularized. Stamens 3. Anthers 2.2–3 mm long (i.e., relatively long); not penicillate; without an apically prolonged connective. Ovary apically glabrous. Styles free to their bases. Stigmas 2; probably red pigmented.

Fruit, embryo and seedling. Fruit small (about 1.5 mm long); slightly indented on one side; not noticeably compressed; papillose, but not ‘sculptured’. Hilum short. Embryo not visible through the opaque pericarp. Endosperm hard.

Abaxial leaf blade epidermis. Costal/intercostal zonation conspicuous. Papillae absent. Long-cells similar in shape costally and intercostally; of similar wall thickness costally and intercostally. Mid-intercostal long-cells rectangular; having markedly sinuous walls. Microhairs present; panicoid-type (but the apical cell quite broad); 33–36–39 microns long; (10.5–)12 microns wide at the septum. Microhair total length/width at septum 2.75–3.43. Microhair apical cells 18–21–24 microns long. Microhair apical cell/total length ratio 0.55–0.62. Stomata common; 36(–39) microns long. Subsidiaries dome-shaped and triangular. Guard-cells overlapping to flush with the interstomatals. Intercostal short-cells common; in cork/silica-cell pairs. Costal short-cells predominantly paired. Costal silica bodies crescentic, or oryzoid, or ‘panicoid-type’; mostly cross shaped (but rather irregular).

Transverse section of leaf blade, physiology. C3; XyMS+. Mesophyll with non-radiate chlorenchyma; without adaxial palisade. Leaf blade with distinct, prominent adaxial ribs; with the ribs more or less constant in size (round topped). Midrib not readily distinguishable; with one bundle only. Bulliforms present in discrete, regular adaxial groups; in simple fans (the groups large). All the vascular bundles accompanied by sclerenchyma. Combined sclerenchyma girders present (with the primaries - some of the other bundles combining abaxial girders with adaxial strands); forming ‘figures’ (I’s, in the primaries). Sclerenchyma all associated with vascular bundles.

Special diagnostic feature. The inflorescence of a few digitately-borne, bracteate spikelets, subtended by a spatheate leaf atop a single elongated culm internode, the plant very sedge-like in appearance.

Classification. Watson & Dallwitz (1994): Arundinoideae; Cyperochloeae. Soreng et al. (2015): Panicoideae; Cyperochloeae. 1 species (C. hirsuta).

Distribution, phytogeography, ecology. Australia.

Xerophytic; species of open habitats. Dry sandy places.

References, etc. Morphological/taxonomic: Lazarides and Watson 1986. Leaf anatomical: studied by us.

Illustrations. • General morphology of C. hirsuta. • Inflorescence detail. Cyperochloa hirsuta. Small bracteate panicle, with subtending leaf to the right.

We advise against extracting comparative information from the descriptions. This is much more easily achieved using the DELTA data files or 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 or lacking specified attributes, distributions of character states within any set of taxa, geographical distribution, and classifications. See also Guidelines for using data taken from Web publications.

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: 11th December 2017.’.