XVI International Botanical Congess

Recent floristic work in the Venezuelan Guayana and for a Catalog of Vascular Plants of Venezuela indicates a total of about 15,500 known species of vascular plants for the country. For the four main floristic regions we obtain the following. Guayana Region: 10,000 species, 23% of these endemic. Andes: 5,000 species, 10% endemic. Coastal Cordilleras: 3,500 species, 7% endemic. Llanos: 2,500 species, 1% endemic. This totals 3,300 endemic species in Venezuela, or 21% of the flora. High and narrow levels of endemism are restricted mainly to the tepuis in the south. The Venezuelan Andes have considerably less areal diversity and endemism than Colombia and Ecuador, except for certain groups like Espeletia. Asteraceae show high levels of endemism in both the Andes and the Guayana Region, but in different intrafamilial groups. The Guayana Region shows the effect of a much greater age, relative isolation, and longer evolutionary history.