1. Lower glume more than 1/3 spikelet length 2
Lower glume 1/8-1/3 spikelet length 24
2. Lower floret male 3
Lower floret sterile 4
3. Spikelets 5.5-7 mm long, densely pilose *P. racemosum (NSW VIC)
Spikelets to 3.5 mm long, glabrous *P. antidotale (NSW SA WA QLD)
4. Spikelet 5-6.5 mm long, apex obtuse *P. miliaceum (NSW VIC TAS SA WA QLD)
Spikelet less then 5 mm long or if 5 mm long then apex mucronate 5
5. Lower glume obtuse to sub-acute (NEEDS CHECKING for P. trichoides and P.incomtum) 6
Lower glume acute to acuminate 8
6. Lower glume less than half spikelet length *P. luzonense (NT)
P. cambogiense
Lower glume at least half spikelet length 7
7. Spikelets 0.8-1.4 mm long *P. trichoides (NT WA QLD)
Spikelets more than 2 mm long *P. incomtum  (QLD)
8. Lower glume at least 3/4 spikelet length 9
Lower glume 1/2-2/3 spikelet length 14
9. Lower glume ±equal to spikelet length or longer 10
Lower glume shorter than spikelet 11
10. Spikelet 2.5-3 mm long P. mindanaense (NT WA QLD)
P. delicatum
Spikelet at least 4 mm long

P. trachyrhachis (NT WA QLD)

P. robustum

11. Annual; inflorescence branches flexuous 12
Perennial; inflorescence branches divaricately spreading 13
12. Leaves glabrous P. seminudum var. seminudum (NT WA QLD)
Leaves hairy P. seminudum var. cairnsianum (NT QLD)
13. Spikelets 3-4.5mm long; fertile floret 2.5-2.75 mm long P. queenslandicum var. queenslandicum (NSW QLD)
Spikelets 5-7mm long; fertile floret 3-3.5 mm long P. queenslandicum var. acuminatum (NSW)
14. Palea absent in lower floret 15
Palea present in lower floret 17
15. Decumbent and glabrous; rooting at nodes P. bisulcatum (NSW VIC QLD)
Tufted; leaves with tubercle-based hairs; not rooting at nodes 16
16. Spikelets 2-2.5 mm long *P. capillare var. capillare (NSW VIC SA WA)
Spikelets 2.5-3.3 mm long *P. capillare var. brevifolium (NSW VIC TAS)
P. capillare var. occidentale
17. Fertile lemma with a lunate scar at base *P. hillmanii (VIC TAS SA)
Fertile lemma without a lunate scar at base 18
18. Upper glume and lower lemma 9-nerved 19
Upper glume and lower lemma 5-7-nerved 20
19. Tufted perennial; leaves with silky hairs P. bombycinum (QLD)
Decumbent annual; leaves with tubercle-based hairs *P. novemnerve (QLD)
20. Culm internodes and base distinctly hairy P. effusum (NSW VIC NT SA WA QLD)
Culm internodes and base glabrous or slightly hairy 21



Inflorescence a fairly narrow panicle, with spikelets thinly dispersed in the inflorescence and occupying less than half the height of the culm ; spikelets acute   22
Inflorescence a large open panicle, with many spikelets occupying at least half the height of the culm; spikelets acuminate 23
Secondary inflorescence branches poorly developed; sandstone soil P. simile (NSW VIC NT QLD)
P. fulgidum, P. effusum var. simile
Secondary inflorescence branches well developed; clay soil P. sp. A (NSW)
23. Annual; inhabits limestone outcrops P. chillagoanum (QLD)
Perennial; habitats other than limestone P. mitchellii (QLD)
24. Lower floret male 25
Lower floret sterile 27
25. Annual *P. schinzii (NSW SA TAS WA)
P. laevifolium
Perennials 26
26. Rhizomatous; lower glume truncate to rounded *P. repens (NSW WA QLD)
Tufted, with a swollen or knotty base; lower glume acute *P. coloratum (NSW VIC WA QLD)
27. Aquatic or swamp grasses 28
Non-aquatic grasses 29
28. Rhizomes thick and spongy; spikelets acuminate P. paludosum (NSW NT QLD)
Rhizomes slender; spikelets acute P. obseptum (NSW VIC QLD)
29. Prostrate grass with inflorescence up to 7 cm long 30
Tufted grass with panicles more than 7 cm long 31
30. Spikelets less than 2 mm long P. pygmaeum (NSW QLD)
Spikelets 2-3 mm long P. lachnophyllum (NSW QLD)
31. Upper floret somewhat shorter than spikelet P. buncei (NSW SA QLD)
Upper floret ±equal to spikelet length 32
32. Inflorescence branches ±flexuous, lower ones solitary 33
Inflorescence branches rigid and spreading, lower ones whorled 35
33. Perennial P. larcomianum (QLD)
Annual or biennial 34
34. Upper glume 9-11-nerved; glumes with distinct rachilla between them *P. gilvum (NSW VIC QLD)
P. laevifolium var. contractum, P. schinzii auct.
Upper glume 7-nerved; glumes without distinct rachilla between them P. laevinode (NSW NT SA WA QLD)
P. whitei
35. Spikelets 2.5-2.8 mm long P. decompositum var. tenuis (NSW NT QLD)
Spikelets 3-3.5 mm long P. decompositum var. decompositum (NSW VIC NT SA WA QLD)
Spikelets 3.5-4.1 mm long P. latzii (NSW WA QLD)
P. decompositum var. acuminatissimum

Key to Panicum derived from Vickery 1975; Webster 1987; Morris 1991; Simon 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