Synonyms: Crosslandia APNI*
Description: Annuals, or perennial herbs with short rhizome. Culms usually tufted, ± angular or subterete, striate or grooved.
Leaves all basal, or also a few over the lower part of culms, occasionally reduced to short-bladed sheaths; ligule a fringe of hairs, or membranous, or absent; inflorescence terminal (very rarely pseudolateral), simple or compound, or head-like, or consisting of a single spikelet; involucral bracts usually leaf-like.
Spikelets solitary or in clusters, terete, angular, or strongly laterally compressed, few to many-flowered; rachilla usually persistent, often winged, rarely spikelets falling off as a whole. Glumes usually spirally arranged, rarely distichous, up to 6 lower ones empty.
Flowers bisexual. Hypogynous bristles absent. Stamens 1–3. Style 2- or 3-fid, with base usually thickened, deciduous, ciliate or glabrous. Nut trigonous or lenticular.
Distribution and occurrence: World: c. 300 species, cosmopolitan, tropical & warm-temp. regions. Australia: 85 species (c. 25 species endemic), all mainland States.
Text by K. L. Wilson
Taxon concept:
| | Key to the species | |
| 1 | Style 3-fid; nuts trigonous | 2 |
| Style 2-fid; nuts biconvex | 4 |
| 2 | Leaf blades very reduced; primary involucral bract glume-like, much shorter than inflorescence | Fimbristylis vaginata |
| Leaf blades present, elongated; primary involucral bract leaf-like, from shorter than to longer than inflorescence
Back to 1 | 3 |
| 3 | Mature spikelets 3–4.5 mm diam., clustered; glumes spirally arranged | Fimbristylis neilsonii |
| Mature spikelets 1–2 mm diam., solitary on ultimate branches; glumes more or less distichous
Back to 2 | Fimbristylis cinnamometorum |
| 4 | Nut with transverse wavy ridges; inflorescence of a single more or less nodding spikelet; leaves usually reduced to sheaths | Fimbristylis nutans |
| Nut not transversely ridged; inflorescence of 1–numerous spikelets (if one, then spikelet is erect); leaf blades present
Back to 1 | 5 |
| 5 | Leaves ligulate | 6 |
| Leaves without ligule
Back to 4 | 10 |
| 6 | Nut distinctly longitudinally striate and transversely trabeculate | 7 |
| Nut smooth, minutely reticulate, or tuberculate
Back to 5 | 8 |
| 7 | Spikelets less than 2 mm diam.; glumes less than 2 mm long | Fimbristylis bisumbellata |
| Spikelets more than 2 mm diam.; glumes more than 2 mm long
Back to 6 | Fimbristylis dichotoma |
| 8 | Glumes appressed pubescent to scaberulous on back, at least near apex | Fimbristylis ferruginea |
| Glumes glabrous on back
Back to 6 | 9 |
| 9 | Glumes more than 4 mm long; spikelets more than 3 mm diam | Fimbristylis tristachya |
| Glumes less than 2 mm long; spikelets less than 3 mm diam
Back to 8 | Fimbristylis polytrichoides |
| 10 | Base of style with long hairs covering nut | Fimbristylis velata |
| Base of style with short hairs
Back to 5 | Fimbristylis aestivalis |
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