| 1. | Glumes longer than lemmas and awned | *D. retroflexa (QLD) |
| Glumes shorter than lemmas and unawned | 2 | |
| 2. | Inflorescence of more than 30 racemes | 3 |
| Inflorescence of less than 30 racemes | 8 |
| 3. | Spikelets 1-flowered |
D. neesii (NT WA QLD) Leptochloa neesii, L. brownii |
| Spikelets 2-4-flowered | 4 | |
| 4. | Leaf sheaths lacking tubercle-based pilose hairs |
D. ligulata (QLD) Leptochloa ligulata |
| Leaf sheaths with tubercle-based pilose hairs | 5 | |
| 5. | Callus apex with long-sericeous to arachnose hairs |
D. simoniana (QLD) Leptochloa simoniana |
| Callus apex glabrous | 6 | |
| 6. | Plants more than 100cm tall; hairs on leaf sheath occurring throughout the sheath |
D. southwoodii (QLD) Leptochloa southwoodii |
| Plants less than 100cm tall; hairs on leaf sheath most dense near sheath apex | 7 (D. panicea) | |
| 7. | Lower lemma mostly more than 1.2 mm long |
*D. panicea subsp. brachiata (QLD) Leptochloa panicea subsp. brachiata, L. mucronata, L. filiformis |
| Lower lemma mostly less than 1.2 mm long |
D. panicea subsp. panicea (QLD) Leptochloa panicea subsp. panicea |
|
| 8. | Racemes widely spreading and stiff |
D. divaricatissima (NSW QLD) Leptochloa divaricatissima |
| Racemes not widely spreading, nor stiff | 9 (D. decipiens) | |
| 9. | Leaves hairy; lemmas densely bearded on the margin |
D. decipiens subsp. peacockii (QLD) Leptochloa decipiens subs. peacockii |
| Leaves glabrous; lemmas shortly hairy on the margin | 10 | |
| 10. | Racemes bearing spikelets to or almost to the base |
D. decipiens subsp. decipiens (NSW QLD) Leptochloa decipiens subsp. decipiens |
| Racemes naked near the base |
D. decipiens subsp. asthenes (NSW QLD) Leptochloa decipiens subsp. asthenes, L. ciliolata, L. debilis |
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