| 1. | Sterile lemmas glabrous | 2 |
| Sterile lemmas with silky hairs | 3 | |
| 2. | Spikelets 3-5mm long, sterile lemmas obtuse | *E. erecta (NSW VIC TAS SA WA QLD) |
| Spikelets more than 10mm long, sterile lemmas ending in awn-like points | *E. longiflora (NSW VIC TAS SA WA QLD) | |
| 3. | Spikelets more than 9mm long | *E. villosa (NSW) |
| Spikelets less than 7mm long | 4 | |
| 4. | Sterile lemmas ending in awn-like points | *E. pusilla (WA) |
| Sterile lemmas acute or obtuse | 5 | |
| 5. | Perennial; sterile lemmas subequal | *E. calycina (NSW VIC TAS SA WA) |
| Annual; upper sterile lemma more than twice length of lower lemma | 6 | |
| 6. | Spikelets 3-3.5mm long | *E. brevifolia var. brevifolia (WA) |
| Spikelets 4-4.5mm | *E. brevifolia var. cuspidata (WA) |
Key to Ehrharta derived from Gardner 1952; Vickery 1975
Taxonomic name: