Tall fleabane (Erigeron sumatrensis), sometimes known as Horseweed. Thought to have originated in South America, this is another very successful pantropical weed that achieves as an efficient wind-blown colonist, with each plant capable to produce a hundred thousand seeds. Its scientific name implies it had already made its way across the Pacific to Indonesia before a European botanist prepared a formal description, and it appears also to have been present in subtropical Africa before colonial era movements of plants and soil. First recorded in Australia in Queensland in 1843, Tall Fleabane seems have not been reported in Victoria for another century (its first collection here being apparently made at Hobson’s Bay in 1945). Over the last thirty years this species has extended its reach elsewhere, invading temperate northern hemisphere locales like London and Poland which were until very recently the exclusive domain of the temperate weed Canada fleabane (E. canadensis), a weed that by contrast, has never done particularly well in Victoria. Different populations have mastered glyphosate and other herbicide resistance in recent years as a result of systematic exposures on agricultural plantations. These Fleabane specimens were growing as a group on the Clifton Hill railway edge of Yarra Park, a few good kicks from the MCG, and are notable as winter individuals of an annual species which mostly grows and flowers in summer.