Some variation here compared with taxonomic photos G. australe:
smaller palmate leaves and thorns on stems;
yellow cf mauve and
between 5 to 8 spiked protruberances either as part of the calyx of the buds or below perhaps in the form of a whorl as they don't match a 5 petaled calyx.
Flower looks like gossypium so wondering if it is a subspecies???
I have no where to start on this. Is it even a grass
WA Herbarium collection Barcode 8098158
WA Herbarium collection Barcode 8098220
WA Herbariun collection Barcode 8098298
WA Herbarium collection Barcode 8793190