| 1. | Spikelet axis not disarticulating between glumes and lowest floret at maturity | 2 |
| Spikelet axis disarticulating between glumes and lowest floret at maturity | 5 | |
| 2. | Lemma with two short awns | *A. strigosa (NSW VIC TAS WA) |
| Lemma 2-toothed or 2-lobed | 3 | |
| 3. | Lower lemma hairy | *A. fatua x A. sativa (QLD) |
| Lower lemma glabrous | 4 | |
| 4. | Awn with distinct column | *A. sativa (NSW VIC TAS SA WA QLD) |
| Awn without a distinct column | *A. byzantina (WA, QLD, NSW) | |
| 5. | Lemma with two short awns | *A. barbata (NSW VIC TAS SA WA) A. alba auct. |
| Lemma 2-toothed or 2-lobed | 6 | |
| 6. | Spikelet axis disarticulating readily between florets at maturity | *A. fatua (NSW VIC TAS NT SA WA QLD) |
| Spikelet axis not disarticulating readily between florets at maturity | 7 | |
| 7. | Lowest lemma 18-25 mm long; callus 1.2-2 mm long | *A. sterilis subsp. ludoviciana (NSW VIC TAS SA WA QLD) A. ludoviciana, A. persica |
| Lowest lemma 25-33 mm long; callus c. 2.6 mm long | *A. sterilis subsp. sterilis (NSW VIC) A. sterilis |
Key to Avena derived from Bor 1970
Taxonomic name: