1. Leaf blades plicate 2
Leaf blades not plicate 3

2. Robust perennial *S. palmifolia (NSW NT SA WA QLD)
Decumbent annual *S. barbata (QLD)

3. Bristles retrorsely barbed *S. verticillata (NSW VIC TAS NT SA WA QLD)

S. adhaerens, S. carnei
Bristles antrorsely barbed 4

4. Annuals 5
Perennials 12

5. Inflorescence an open to contracted panicle of racemes 6
Inflorescence a tightly contracted false spike 7

6. Inflorescence contracted *S. italica (NSW VIC TAS SA WA QLD)
Inflorescence open *S. dielsii (NT SA WA QLD)

7. Upper glume 1/2 spike length 8
Upper glume more than 1/2 spike length 9

8. Spikelets less than 2.5 mm long *S. pumila subsp. subtesselata (NSW NT QLD)

S. pallide-fusca
Spikelets c. 3 mm long *S. pumila subsp. pumila (NSW VIC SA WA QLD)

S. glauca, S. lutescens

9. Spikelets not turgid; upper floret very finely rugose *S. viridis (NSW VIC TAS SA QLD)
Spikelets turgid; upper floret coarsely rugose 10

10. Spikelets more than 3.5 mm
S. queenslandica (NT WA QLD)
Spikelets up to 3.4 mm long 11

11. Spikelets 2.5-2.9 mm long; upper glume 3/4 spikelet length S. surg ens (NSW NT WA QLD)

S. brownii
Spikelets 3-3.4 mm long; upper glume from 80% to almost as long as spikelet S. apiculata (NT WA QLD)

12. Inflorescence a loosely contracted panicle 13
Inflorescence a tightly contracted false spike 15

13. Inflorescence with spikelets clustered along primary branches S. oplismenoides (NT QLD)
Inflorescence with spikelets ±uniformly arranged 14

14. Spikelets c. 4 mm long S. australiensis (NSW NT QLD)
Spikelets c. 3 mm long S. paspalidioides (NSW QLD)

15. Inflorescence (excluding bristles) c. 4 mm wide *S. parviflora (NSW VIC TAS SA WA QLD)

S. geniculata var. geniculata, S. geniculata var. pauciseta,

S. gracilis

var. gracilis, S. gracilis var. pauciseta
Inflorescence (excluding bristles) c. 6-8mm wide 16

16. Bristles purple; upper glume 7-nerved *S. incrassata (NT WA QLD)

S. porphyrantha
Bristles fulvous; upper glume 3-5-nerved 17

17. Inflorescence 7-25cm long; leaf blades 3-10 mm wide *S. sphacelata var. anceps (NSW WA QLD)

S. anceps
Inflorescence 20-50cm long; leaf blades 10-17 mm wide *S. sphacelata var. splendida (QLD)

S. splendida

Key to Setaria derived from Vickery 1975; Webster 1987

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