| 1. | Lemma awn absent | 2 |
| Lemma awn present | 3 | |
| 2. | Glumes subequal | D. talariata (NSW VIC) |
| Glumes distinctly unequal | D. nudiflora (NSW) | |
| 3. | Lemma shorter than or subequal to upper glume | 4 |
| Lemma distinctly longer than upper glume | 40 | |
| 4. | Lower glume usually longer than upper, or glumes subequal | 5 |
| Lower glume slightly shorter than upper | 15 | |
| 5. | Awn attached above lower 1/3 of lemma | 6 |
| Awn attached in lower 1/3 of lemma | 11 | |
| 6. | Awn attached just below apex of lemma | 7 |
| Awn attached ± at middle of lemma | 10 | |
| 7. | Lemma c. 3/4 the length of glumes | D. imbricata (NSW VIC QLD) |
| Lemma ± the length of glumes | 8 | |
| 8. | Spikelets 3.6-5 mm long | D. talariata (NSW VIC) |
| Spikelets to 3.5 mm long | 9 | |
| 9. | Plants tufted | D. innominata (NSW VIC TAS) |
| Plants stoloniferous | D. ramosa (NSW VIC) D. sp. aff. nudiflora |
|
| 10. | Spikelets 3.5-5 mm long | D. densa (VIC TAS SA) |
| Spikelets c. 3 mm long | D. mesathera (NSW) | |
| 11. | Lemma ± equal to length of glumes | D. apsleyensis (TAS) |
| Lemma shorter than length of glumes | 12 | |
| 12. | Lemma ± 2/3 length of glumes | D. quadriseta (NSW VIC TAS SA WA) D. quadriseta var. cylindrica |
| Lemma ± 1/2 length of lower glume | 13 | |
| 13. | Inflorescence not very dense | D. drummondii (WA) |
| Inflorescence dense | 14 | |
| 14. | Spikelets 8mm long; inflorescence 9 cm long | D. lawrencei (TAS) |
| Spikelets c. 6mm long; inflorescence 1-7 cm long | D. inaequalis (WA) | |
| 15. | Inflorescence a ± contracted panicle or if loose branches bearing spikelets from their bases |
16 |
| Inflorescence ± loose with spreading branches naked at base |
31 | |
| 16. | Awn attached in lower 1/3 of lemma | 17 |
| Awn attached above lower 1/3 of lemma | 18 | |
| 17. | Spikelets 3.5-6 mm long | D. monticola (NSW VIC TAS) |
| Spikelets 6-7 mm long | D. valida (NSW) D. monticola var. valida, Deyeuxia aff. nudiflora |
|
| 18. | Awn attached in middle 1/3 of lemma | 19 |
| Awn attached in upper 1/3 of lemma | 21 | |
| 19. | Spikelets more than 5 mm long | 20 |
| Spikelets less than 5 mm long | 23 | |
| 20. | Rachilla bristle to 2 mm long with hairs to 1 mm long | D. densa (VIC TAS SA) |
| Rachilla bristle to 0.5-1 mm long, glabrous or sparsely hairy | D. carinata (NSW VIC TAS) | |
| 21. | Awn exceeding lemma by lemma length | D. minor (NSW VIC TAS SA) |
| Awn exceeding lemma by up to 1/2 lemma length | 22 | |
| 22. | Leaf blades 4-6 mm wide; culms more than 1 mm diam. just below the dense inflorescence |
D. crassiuscula (NSW VIC) |
| Leaf blades 1-3 mm wide; culms 0.5-0.75 mm diam. just below the loosely contracted inflorescence |
D. rodwayi (NSW VIC TAS QLD) | |
| 23. | Spikelets 4-7 mm long | 24 |
| Spikelets less than 4.5 mm long | 26 | |
| 24. | Awn ± as long as lemma; inflorescence 8-17 x 0.8-2 cm | D. brachyathera (NSW VIC TAS) |
| Awn much shorter than lemma; inflorescence 3-9 x 4-6 cm | 25 | |
| 25. | Callus hairy; awn thin; ligule 4-11 mm long | D. pungens (VIC) |
| Callus naked; awn thick; ligule 1 mm long | D. angustifolia (NSW) | |
| 26. | Awn as long as or longer than lemma | 27 |
| Awn shorter than lemma | 28 | |
| 27. | Inflorescence a contracted panicle; culms to 40 cm tall | D. appressa (NSW) |
| Inflorescence a loosely contracted panicle; culms to 20 cm tall | D. affinis (NSW VIC) | |
| 28. | Rachilla not or hardly produced into a bristle | D. imbricata (NSW VIC QLD) |
| Rachilla distinctly produced into a glabrous or hairy bristle | 29 | |
| 29. | Awn 1-2mm long; inflorescence a tightly contracted panicle | D. crassiuscula (NSW VIC |
| Awn minute; inflorescence a loosely contracted panicle | 30 | |
| 30. | Spikelets 2.5-3 mm long | D. contracta (NSW VIC TAS) |
| Spikelets 3.5-4 mm long | D. microseta (NSW) | |
| 31. | Awn arising from middle 1/3 of lemma | 32 |
| Awn arising from upper 1/3 of lemma | 34 | |
| 32. | Anthers 1.5-2.2 mm long | D. frigida (NSW VIC TAS) D. accedens |
| Anthers 0.5-0.6 mm long | 33 | |
| 33. | Spikelets 3.5-4.2 mm long | D. rodwayi (NSW VIC TAS QLD) |
| Spikelets 2.5-3 mm long | D. contracta (NSW VIC TAS) | |
| 34. | Lemma ± smooth or sparsely scaberulous | 35 |
| Lemma distinctly scaberulous | 37 | |
| 35. | Awn ± thick, exceeding lemma by more than 1/2 lemma length | D. brachyathera (NSW VIC TAS) |
| Awn very fine, hardly exceeding lemma | 36 | |
| 36. | Rachilla not or produced into a bristle 0.3-0.5 mm long |
D. decipiens (NSW VIC TAS QLD) |
| Rachilla produced into a bristle 0.8 mm long | D. parviseta var. boormani (NSW) | |
| 37. | Awn ± as long as lemma, strongly exserted, reflexed | D. reflexa (NSW) |
| Awn minute, hardly exserted | 38 | |
| 38. | Inflorescence 6-9 cm long, with stiffly spreading branches | D. microseta (NSW) |
| Inflorescence 9-30 cm long, with lax branches | 39 | |
| 39. | Spikelets ± 2.5 mm long | D. contracta (NSW VIC TAS) |
| Spikelets 3-4 mm long | D. scaberula (NSW VIC TAS) D. benthamiana |
|
| 40. | Spikelet callus glabrous | D. breviglumis (NSW TAS) |
| Inflorescence rather long and loose; leaves flat | 42 | |
| 41. | Inflorescence short with stiff branches; leaves setaceous | D. gunniana (NSW VIC TAS QLD) |
| Inflorescence rather long and loose; leaves flat | 42 | |
| 42. | Awn ± as long as lemma, exserted, reflexed | D. reflexa (NSW) |
| Awn very short, hardly exceeding lemma | 43 | |
| 43. | Lemma not or hardly scaberulous | D. decipiens (NSW VIC TAS QLD) |
| Lemma distinctly scaberulous | 44 | |
| 44. | Spikelets c. 5 mm long; awn 0.7-1 mm long | D. acuminata (NSW) |
| Spikelets less than 4 mm long; awn 0.2-0.4 mm long | 45 | |
| 45. | Spikelets 1.5-2.5 mm; anthers c. 0.7 mm long | D. parviseta var. parviseta (NSW VIC QLD) |
| Spikelets 3-3.8 mm; anthers c. 1.3 mm long | D. mckiei (NSW) |
Key to Deyeuxia derived from Vickery 1940; Morris 1990; Walsh 1991, 1992
Taxonomic name: