Description: Tufted or rhizomatous annuals or perennials; annuals frequently amphicarpous (i.e. with basal spikelets hidden amongst leaf sheaths). Culms nodeless or 1(-3)-noded above the base, terete to triquetrous, glabrous.
Leaves mostly reduced to a mucro on a sheath, occasionally longer blade present; ligule membranous.
Aerial inflorescence pseudolateral, head-like or a single spikele, rarely shortly branchedt; lowest involucral bract culm-like, usually erect.Spikelets mostly sessile, many-flowered. Hypogynous bristles 2–6(-10), filiform and retrorsely scabrous, or flattened and irregularly plumose, or occasionally very reduced. Stamens 2 or 3. Style 2- or 3-fid. Basal (amphicarpous) spikelets present in some annual species.
Nuts lenticular or trigonous, smooth or transversely rugose. Basal spikelets with longer, 3-fid styles and larger nuts.
Distribution and occurrence: World: c. 50 species, cosmopolitan. Australia: 9 species (3 species endemic), all mainland States.
Previously included in Schoenoplectus. The species are commonly divided between two sections: sect. Schoenoplectiella (the small annual species, which are often amphicarpous, e.g. S. dissachantha and S. laevis) and sect. Actaeogeton (more robust annuals and rhizomatous perennials, not amphicarpous; e.g. S. lineolata, S. mucronata).
Text by KL Wilson (Nov 2015); edited KL Wilson (March 2019)
Taxon concept:
| | Key to the species | |
| 1 | Robust plants with culms usually 2–8 mm (rarely less) in diam.; culms triquetrous[; nuts smooth] | Schoenoplectiella mucronata |
| Slender plants with culms no more than 1 mm in diam., terete to subtrigonous | 2 |
| 2 | Nuts smooth | 3 |
| Nuts transversely rugose
Back to 1 | 4 |
| 3 | Glumes 1.7–2.2 mm long, obtuse; stamens 2; plants tufted | Schoenoplectiella laevis |
| Glumes 3.8–4.5 mm long, acute; stamens 3; plants at least shortly rhizomatous
Back to 2 | Schoenoplectiella lineolata |
| 4 | Glumes yellow-tinged, glabrous; stamens 2 or occasionally 3; nut with acutely angled transverse ridges, dark brown to black, subglobose to obovoid; hypogynous bristles present (rarely very short) | Schoenoplectiella dissachantha |
| Glumes red-tinged, ciliolate on margins; stamens 3; nut with broadly rounded transverse ridges, black, obovoid; hypogynous bristles absent
Back to 2 | Schoenoplectiella erecta |
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