XVI International Botanical Congess

Fossil leaves of early angiosperms are found in different regions of the world. They show a wide variety of construction morphology strategies, with apparently homologous characters. They are different from contemporaneous gymnosperm ones. In Southern South America, the fossil record comprises several sites of Cretaceous age, with about 30 species or types. Most of the constructional patterns found in South America are also found in other continents at the same time. They show apparent homologous characters, and implied common ancestors should not be difficult to found. However, cases of homoplasy should be expected, given their paleobiogeographical distribution. Other patterns are apparently South American novelties, that only in the Upper Cretaceous become widespread in other regions of the world. A few patterns were endemic to Southern South America by early Late cretaceous. One of them repeats construction morphology strategies largely tested in Gondwanaland Mesozoic gimnosperm plants.