abstract
Thirty-eight species of vascular plants have been recorded on Marion and Prince Edward Islands, of which 13 are alien. On
Marion Island 4 of the 13 aliens are classed as transient aliens, one as a persistent alien and 8 as naturalized aliens. Four of the naturalized aliens show a restricted distribution and four are spread widely over the island. Only one alien species occurs on Prince Edward Island and is considered to be naturalized. It appears that 8 of the alien species on Marion Island were introduced by sealers during the last century. Five species have been introduced at the meteorological station since 1948. Four of the aliens have disappeared from the island since 1966. Only two of the alien species compete aggressively with the natural vegetation.