| 1. | Pedicelled spikelet absent or reduced to a minute rudiment | S. angustum (NT QLD) Sorghum angustum |
| Pedicelled spikelet well developed | 2 | |
| 2. | Annuals | 3 |
| Perennials | 4 | |
| 3. | Caryopsis apex with a tuft of hairs |
S. intrans (NT WA) Sorghum intrans, S. extans |
| Caryopsis apex glabrous | S. timorense (NT WA QLD) Sorghum timorense, S. australiense, S. amplum, S. brachypodum, S. bulbosum, S. ecarinatum, S. matarankense, S. stipoideum |
|
| 4. | Awns of sessile spikelet 0-0.25 cm long | S. leiocladum (NSW VIC QLD) Sorghum leiocladum |
| Awns of sessile spikelet 3.5-9 cm long | S. plumosum (NT WA QLD) Sorghum interjectum, S. plumosum var. teretefolium, S. grande |
Key to Sarga derived from Spangler
Taxonomic name: