Those three findings have been feautured before in older postings.
The reader can find Sheep sorrel(Acetosella vulgaris) here, Plantain (Plantago Lanceolata) here and Blackberry (Rubus fruticosus) here,
and here is some more information.
Those three plants have been some of the first introduced species in Australia, porposely seeded around the continent by early explorers.
Robert Brown, the botanist travelling with Flinders found Plantago well estabilished in the Sydney basin back in 1802, only fifteen years after the first British landing at Botany Bay.
Baron Ferdinand Jacob Heirich Von Muller,1870s Victorian Government botanist, Director of Melbourne Botanic Gardens used to scatter Blackberry seeds through the wilderness during botanical expeditions.
He famously used to carry a packet of Blackberry seeds with him and whenever he boiled his billy, he scattered a few round the ashes of his fire.