| 1. | Lower glume of sessile spikelet with a distinct sub-apical arch of long cilia |
2 |
| Lower glume of sessile spikelet without a distinct ciliate sub-apical arch |
5 | |
| 2. | Sessile spikelet 5-6 mm long; pedicelled spikelet male | D. setosum (NSW TAS QLD) |
| Sessile spikelet 3-4.5 mm long; pedicelled spikelet sterile | 3 | |
| 3. | Lower glume of pedicelled spikelet obovate with sub-apical arch conspicuous, cilia erect from surface; robust annuals |
D. sericeum subsp. polystachyum (NT WA QLD) D. superciliatum, D. tenuiculmum |
| Lower glume of pedicelled spikelet linear to narrowly ovate, cilia not erect from surface; annuals or perennials |
4 | |
| 4. | Spikelets 4.5 x 1-1.4 mm; lower glume 9-10-nerved; raceme usually more than 4 cm long; perennials |
D. sericeum subsp. sericeum (NSW VIC TAS NT SA WA QLD) D. affine |
| Spikelets 4 x 1 mm; lower glume 5-7-nerved; racemes less than 4 cm long; annuals |
D. sericeum subsp. humilius (NSW NT SA WA QLD) D. humilius |
|
| 5. | Racemes usually 2 or more and pedunculate; glumes hairy to some degree |
6 |
| Racemes usually single, if 2 or more then sessile; glumes glabrous or sparsely hairy |
9 | |
| 6. | Lower glume of sessile spikelet ±obovate | 7 |
| Lower glume of sessile spikelet ±oblong | 8 | |
| 7. | Peduncles glabrous | *D. caricosum (QLD |
| Peduncles covered with downy hairs | *D. aristatum (NT WA QLD) | |
| 8. | Spikelets at least 4.5 mm long, acute; pedicelled spikelet male; stigmas distinctly protruding at maturity |
D. fecundum (NT WA QLD) |
| Spikelets to 4 mm long, obtuse to truncate; pedicelled spikelet sterile; stigmas not distinctly protruding at maturity |
*D. annulatum (NT WA QLD) | |
| 9. | Racemes up to 6cm long; sessile spikelets 3-4 mm long | D. tenue (NSW QLD) |
| Racemes more than 6cm long; sessile spikelets 6-8 mm long | D. queenslandicum (QLD) |
Key to Dichanthium derived from de Wet and Harlan 1968; Simon 1989b
Taxonomic name: