| 1. | Palea absent or minute, rarely up to 1/3 lemma length | 2 |
| Palea present, from 1/2 as long as lemma | 12 | |
| 2. | Lemma awned | 3 |
| Lemma awnless | 5 | |
| 3. | Inflorescence with spreading branches, naked at base | A. venusta (NSW VIC TAS) |
| Inflorescence ± contracted, bearing spikelets from near base of branches | 4 | |
| 4. | Spikelet 3-3.5 mm long with awn arising near tip of lemma | A. muelleriana (NSW VIC TAS) |
| Spikelet c. 2 mm long with awn arising back of lemma | A. boormanii (NSW) | |
| 5. | Inflorescence contracted | 6 |
| Inflorescence open | 7 | |
| 6. | Perennial; culms to 90 cm tall; sheaths greenish; inflorescence 10-35 cm long; spikelets 1.8-2.2 mm long | A. bettyae (NSW QLD) |
| Annual; culms to 25 cm tall; sheaths purplish; inflorescence 20-60 cm long; spikelets 2.2-3.5 mm long | A. muelleriana (NSW VIC TAS) | |
| 7. | Inflorescence 12-35 cm long |
A. propinqua (NSW VIC) A. sp. E and A. sp. F in AusGrass |
| Inflorescence to 12 cm long | 8 | |
| 8. | Leaf blades 0.25-1.4 mm wide | 9 |
| Leaf blades 2-2.5 mm wide | 11 | |
| 9. | Inflorescence branches flexuose | A. joyceae (NSW) |
| Inflorescence branches stiffly spreading or divaricate | 10 | |
| 10. | Spikelets 1.5-2mm long; leaves mostly basal | A. parviflora (NSW VIC TAS) |
| Spikelets 2.3-3mm long; leaves scattered along culm | A. australiensis (NSW VIC TAS) | |
| 11. | Lemmas 1.3-1.8mm long; ligule to 5 mm long, laciniate | A. thompsoniae (NSW VIC TAS) |
| Lemmas 2-2.5mm long; ligule 1-3 mm long, entire | A. diemenica (TAS) |
|
| 12. | Ligule wider than long | 13 |
| Ligule as long as or longer than wide | 14 | |
| 13. | Lemma awnless | *A. capillaris var. capillaris (NSW VIC TAS SA WA) A. tenuis var. tenuis |
| Lemma shortly awned | *A. capillaris var. aristata (VIC) A. tenuis var. aristata |
|
| 14. | Rhizomatous; inflorescence usually open and loose | *A. gigantea (NSW VIC TAS SA WA QLD) |
| Stoloniferous; inflorescence usually contracted and dense | *A. stolonifera (NSW VIC TAS WA QLD) |
Key to Agrostis derived from Vickery 1941; Morris 1990; Jacobs 2001b; Jacobs 2009