Leaf fossils collected in 1908 from the Arauco–Concepción Coal Measures of Chile (the Lota–Coronel flora) during a Swedish expedition to southern South America are formally assigned to the important Gondwanan family Proteaceae as Proteaceaefolia araucoensis R.J.Carp. & McLoughlin gen. nov., sp. nov. This is the oldest South American record of macrofossils that can be assigned to Proteaceae with confidence due to the likelihood of the age dating to the latest Paleocene. The fossils lack cuticle but the large, lobed and minutely toothed form is consistent only with extant species of the subfamily Grevilleoideae (notably, Orites excelsus R.Br.) that are confined to eastern Australian rainforests. A new assessment of the Swedish Lota–Coronel collection and review of previous palynological and macrofossil studies, also provide evidence of the strong biogeographic connection that existed between southern South America and Australasia during the early Paleogene, and contradict a traditional view that several Chilean floras of this age consist wholly or largely of Neotropical taxa. Notable austral taxa include Casuarinaceae (as abundant pollen), diverse Podocarpaceae (as both foliage and pollen) and likely Cunoniaceae (leaves). No taxa with clearly Neotropical nearest living relatives have been found to date, but previous conclusions for a warm and very wet early Paleogene climate are supported.