Annual Pearlwort, Common Pearlwort, New Zealand Moss
Introduced annual forb about 10cm tall. Leaves opposite each other, 0.3-1cm long, 0.5-1.5mm wide, linear, usually more or less hairy towards the base, apex pointed, usually with a long fine point drawn out into a bristle. Flowers with 4 sepals, green to pale brownish pink, about 2mm long, and 4 petals, minute or absent. Flowers solitary, or in open groups at the tops of the stems.
PlantNET description: http://plantnet.rbgsyd.nsw.gov.au/cgi-bin/NSWfl.pl?page=nswfl&lvl=sp&name=Sagina~apetala