Phytogeography and organization of genetic diversity in the genus Passiflora

The genus Passiflora comprises 450 to 500 species of herbaceous and woody lianas most of which occur in tropical forest of America, few species were collected in Asia, Australia and in West Pacific islands. The most important center of diversity of the genus, with about 150 species collected, is in the cloud forest of Andean cordilleras. Another center of diversity, with about a hundred species collected, is in the high and lower cloud forest of Central America and West Indies. About 80 species were collected in Guianese and in Brazilian Shields, about twenty species are widespread in tropical America. In America the centers of diversity are located in mountain forests where rainfall is particularly high, these areas would be forest refugia and also refugia for Heliconius or passion flower butterflies, example of coevolution between insects and plants. In Guianas one refugium would be locate in the northeasthern part of French Guiana, in Kaw mountain region. This area is a center of endemism for Passiflora, the botanical explorations permit to collect about twenty species belonging to six different subgenera. The study of characters to four of these subgenera (Astrophea, Distephana, Passiflora and Plectostemma), concerning phytogeography, foliar forms, vegetative architecture and resistance to disease, allows to estimate the evolutive connections of species groups. The biodiversity study of Guianan passion flowers permitted to determine genetic resources of these plants interesting the improvement of passion fruit culture, widespread in tropical regions of the world.