Comesperma drummondii Drummond's Milkwort
This as its name suggests is a member of the Polygalaceae and so is related to the UK's much smaller herbaceous grassland Milkwort species such as Polygala vulgaris. The UK species P. vulgaris can be several different colours and Comesperma drummondii similarly can pink, blue or purple. Here in western Australia it is a shrub growing in poor sandy soil and often with a specialised insect pollination mechanism.