Ferraria crispa Black Flag Invasive Weed
This garden escape is a native of South Africa and is a known invasive foreign species. It tends to grow in coastal districts and these plants were part of a large clump at the roadside not far from the beach.
This weed is one of Western Australia's ten most invasive weeds still on sale in nurseries and garden centres. It was mentioned in the "Jumping the Garden Fence" report about Australian garden escapes.