XVI International Botanical Congess

The Guiana Shield includes parts of Brazil, Venezuela, Guyana, Suriname and French Guiana. It consists of pre-Cambrian metamorphic rocks overlaid by the sandstone Roraima Formation, eroded to form table mountains (tepuis). Much of the area is tropical lowland rainforest below 1000m, but with many tepuis over 2000m, up to 3000m (Neblina). About 40 moss families, 125 genera and 410 species are recorded. Endemism is generally rare in mosses, and few Guiana Shield mosses can be reliably described as endemic. However, the area does appear to be a centre of diversity for some families, including the Leucobryaceae, Calymperaceae and Dicranaceae. Under-represention of some families (e.g. Pottiaceae) may reflect either lack of suitable habitats or inadequate collecting. Common neotropical mosses recently collected new to the area indicate that the moss diversity of the Guiana Shield is still inadequately known.