| 1. | Some involucral spikelets a little above others | 2 |
| Involucral spikelets all at same level | 3 | |
| 2. | Involucral spikelets to 10 mm long, with golden tubercle-based hairs | T. intermedia (QLD) |
| Involucral spikelets 19-28 mm long, glabrous | T. avenacea (NSW VIC NT SA WA QLD) | |
| 3. | Fertile spikelet with an awn 7-9 cm long and a pungent callus 3-4 mm long |
T. arguens (NT WA QLD) T. frondosa |
| Fertile spikelet with an awn less than 7 cm long and a callus 1-3 mm long | 4 | |
| 4. | Perennial; involucral spikelets 8-14 mm long; sessile spikelets 6-11mm long | T. triandra (NSW VIC TAS NT SA WA QLD) T. australis |
| Annual; involucral spikelets 4-7 mm long; sessile spikelets 4-5mm long | *T. quadrivalvis (NSW NT WA QLD) |
Key to Themeda derived from Blake 1969; Henty 1969; Simon 1985
Taxonomic name: