1. Annual; lower glume 0.5 mm long G. drummondii (WA)
Perennial; lower glume more than 1.5 mm long 2

2. Lower glume 3-5-nerved, 7-8 mm long G. latispicea (NSW)
Lower glume 1-nerved, 1.5-5.5 mm long 3

3. Lemmas more than 5.5 mm long 4
Lemmas 3-5 mm long 5

4. Lower glume 2-3 mm long *G. fluitans (TAS)
Lower glume 5-7 mm long G. australis (NSW VIC TAS SA WA)

5. Spikelets 5-12 mm long *G. maxima (NSW VIC TAS WA QLD)
G. aquatica
Spikelets 13-25 mm long 6

6. Lemma toothed at apex; paleas slightly longer than lemma G. declinata (NSW VIC TAS SA WA)
Lemma ±entire at apex; paleas shorter than lemma *G. plicata (VIC TAS)

Key to Glyceria derived from Wheeler, Jacobs and Norton 1990

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