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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.

Distribution, phytogeography, ecology. Australia.

Xerophytic; species of open habitats. Dry sandy places.

References, etc. Morphological/taxonomic: Lazarides and Watson 1986. Leaf anatomical: this project.

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


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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: 13th November 2017. delta-intkey.com/grass’.

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