Hastate Orache, Mat Saltbush
Introduced annual forb to 80cm tall or prostrate. Lower leaves opposite each other, 1.5-8cm long, triangular, scurfy to hairless, margins entire to sparsely toothed. Upper leaves upper leaves alternating along the stems, flat, margins entire, decreasing in size upwards. Flowers small (less than 3mm across), male and female flowers on the same plant, in mixed clusters forming interrupted panicles at the ends of the stems.
PlantNET description and line drawing of fruiting body: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Atriplex~prostrata
Note that the description in G.M. Cunningham, WE Mulham, PL Milthorpe and J H Leigh (1981 and later printings) Plants of Western New South Wales, of Atriplex prostrata (page 243) is actually of the native plant, Atriplex pumilio.