Cockburn Island, off the north-east Antarctic Peninsula, is important in the history of Antarctic terrestrial biology as it was here where the first botanical collections were made by JD Hooker in 1843. These, and a subsequent collection made by IM Lamb one hundred years later, are described here. A much more detailed survey of the vegetation of the island was made in 1989. At least nine moss, 34 lichen, three cyanobacteria and one alga taxa were recorded, and the floristic composition of several distinct communities assessed. The floristically most interesting and diverse sites are on the island's 250 m high plateau which possesses seepage areas and welldeveloped networks of polygons and stone circles. The vegetation is similar to that occurring on the mainly sedimentary deposits and rocks of nearby James Ross and Seymour Islands, but significantly different to that on the more acidic soils and rocks which predominate throughout much of the maritime Antarctic.