1. Ligule a fringe of long stiff hairs; plants perennial 2
Ligule absent or with cilia to 1.5 mm long; plants annual 4

2. Spikelets awnless *E. pyramidalis (WA)
Spikelets mucronate or awned 3

3. Culms less than 1 m tall; upper leaf blades less than 10 mm wide E. picta (QLD)
Culms to 3.6 m tall; upper leaf blades to 20 mm wide

*E. polystachya (NT QLD)

E. praestans auct.

4. Inflorescence axis ±smooth; glumes and
lower lemma ±smooth and lightly scabrous on nerves
E. lacunaria (NSW SA)
Inflorescence axis ±strongly scabrous;
glumes and lower lemma ±scabrous both on and between nerves

5. Spikelets at maturity very turgid and subglobose 6
Spikelets at maturity less turgid and subglobose 8

6. Spikelets c. 4.5 mm long; lower lemma with a median longitudinal groove E. turneriana (NSW NT SA QLD)
Spikelets c. 4 mm long; lower lemma without a median longitudinal groove 7

7. Spikelets pallid; grain whitish *E. frumentacea (NSW VIC TAS WA QLD)
Spikelets purplish to blackish-brown; grain brownish *E. esculenta (NSW VIC TAS SA WA QLD)
E. utilis

8. Mature grain 2.5-3.5 mm long 9
Mature grain less than 2.5 mm long 11

9. Spikelets without well-developed
anthocyanin pigmentation; upper floret 3.5-4.5 mm long
*E. oryzoides (NSW WA)
Spikelets with well-developed anthocyanin
pigmentation; upper floret 4.5-6.5 mm long

10. Upper floret 5-6.5mm long; anthers 1.5-2.1 mm long E. kimberleyensis (NT WA QLD)
Upper floret 4.5-5mm long; anthers 2.5-2.8 mm long E. macrandra (WA)

11. Upper glume noticably awned 12
Upper glume not or scarcely awned 14

12. Upper glume with awns c. 3.5 mm long E. dietrichiana (NT SA QLD)
Upper glume with awns up to 7mm long 13

13. Spikelets 3-4.2 mm long, with purplish awns E. telmatophila (NSW WA QLD)
E. walteri auct.
Spikelets 4-4.5 mm long, with pale awns E. elliptica (NT WA QLD)

14. Inflorescence drooping with soft flexuous
branches; racemes compound
*E. crus-pavonis (NSW SA WA QLD)
Inflorescence usually erect with branches
stiffly spreading; racemes simple

15. Upper floret apex gradually narrowing into
a firm tip to 1.5 mm long
*E. muricata var. microstachya (NSW VIC)
E. microstachya
Upper floret apex abruptly terminating in a
fragile tip to 0.5 mm long

16. Spikelets 3.5-5mm long excluding cusps and awns when present E. inundata (NSW SA QLD)
Spikelets less than 3.5 mm long 17

17 Spikelets awnless to cuspidate, close
together in 4 irregular rows; grain 1.1-1.2 mm wide, whitish
*E. colona (NSW VIC NT SA WA QLD)
Spikelets awnless to strongly awned, not in 4 rows; grain 1.2-1.6 mm wide, pale brownish *E. crus-galli (NSW VIC TAS NT SA WA
E. crus-galli subsp. hispidula

Key to Echinochloa derived from Vickery 1975; Michael 1983; Webster 1987;
Scholz 1992

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