1. Sterile lemmas acuminate 2
Sterile lemmas obtuse or acute 4
2. Spikelet 8-12mm long T. acuminata (NSW VIC TAS SA)
Spikelet 4-6mm long 3
3. Leaf blades tightly inrolled T. oreophila var. oreophila (TAS)
Ehrharta oreophila
Leaf blades flat T. oreophila var. minor (TAS)
Ehrharta oreophila var. minor
4. Sterile lemmas scabrous T. distichophylla (VIC TAS SA)
Sterile lemmas smooth 5
5. Spikelets ±8mm long T. laevis (WA)
Spikelets ±6mm long 6
6. Leaf blades flat, more than 2 mm wide, not stiff T. juncea (NSW VIC TAS SA QLD)
Leaf blades folded, less than 1 mm wide, stiff T. turfosa (NSW VIC SA)

Key to Tetrarrhena derived from Willis 1970; Willemse 1982 under Ehrharta; Walsh 1989

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