The Marcgraviaceae of Colombian mazonia: preliminary study on its diversity, distribution and phytogeography

Abstract

The Marcgraviaceae is a small-sized neotropical family with 8 genera and perhaps 110 species mainly distributed in Colombian Amazonia, Costa Rica, Panama and Andean Colombian and Peruvian montane rain forests. Five genera and 27 species were recorded from Colombian Amazonia, where the most diverse genus was Marcgravia (13 species), followed by Souroubea (6 species), Marcgraviastrum (4 species), Norantea and Ruyschia with 2 species each. Based on a phenetic biogeographical classification, comparisons of diversity,  distribution, affinity, and endemism among  different Neotropical regions are provided. Although the knowledge of the Marcgraviaceae is still incomplete, some features with regard to their diversity and distribution in the Neotropic begin to emerge: 1. The Marcgraviaceae are more diverse in Westem Amazonia, particularly Colombian Amazonia, than other are as (e.g., southern Mexico and southern Brazil); 2. Narrow endemic species appears to be low (ca. 24%); 3. Fifty percent of the Marcgraviaceae have a restricted distribution to a phytogeographical Region level; 4. The distribution of the numerous wide-ranging species are more or less patchy; 5. This family showed its highest endemism in northwestern of South America (Peru and Colombia); 6. The geologic history of the Andes has played an important role in the distribution and evolution of the Marcgraviaceae. For instance, most of the species diversity of several genera tends to be concentrated in Central America (Norantea), the Colombian Andean Region (Marcgraviastrum), or Westem Amazonia (Marcgravia), and these areas correspond to are as of different geologic age. The Marcgraviaceae seems to have originated in South America and thus probably migrated to Central America.