1. Glumes 2-3 mm long A. whitei (QLD)
Glumes 3-7 mm long 2

2. Awn attached just above middle of lemma 3
Awn attached well above middle of lemma 7

3. Lemmas 7-10 in number, 3.5-4 mm long A. fluitans (NSW VIC)
A. gracilis
Lemmas 4-7 in number, more than 6 mm long 4

4. Plant weakly rhizomatous; apex of leaf
blade almost pungent
A. sinuatus (NSW VIC SA TAS)
Plant densely tufted; apex of leaf blade long and slender 5

5. Glumes narrow, lower 3-4 mm long, upper 4-5 mm long A. neesii (NSW VIC TAS)
Glumes broad, lower c. 4 mm long, upper to 7 mm long 6

6. Lemma evenly tapering from body of lemma A. nervosus (NSW VIC SA WA)
Lemma with drawn out, chartaceous apex A. macrorhinus (NSW VIC TAS SA WA)

7. Lemma apex with nerves extending into bristles 8
Lemma apex with nerves not extending into bristles 9

8. Lemma (excluding awn and bristles) at least 6 mm long A. archeri (VIC TAS SA)
A. archeri var. papillosus
Lemma (excluding awn and bristles) up to 5.5 mm long A. vickeryae (WA)

9. Lemma densely hispid A. recurvatus (VIC TAS SA)
Lemma scabrous or papillose A. pithogastrus (NSW VIC)

Key to Amphibromus derived from Jacobs & Lapinpuro 1986

Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith