Summary
The terminology of the Amazonian forest types on inundated ground has been much confused in the past. In Brazil the terms várzea and igapó have been used in several different ways by various workers in different disciplines or even within a single discipline such as botany. These terms are also used differently in the lower and upper parts of Amazonian Brazil and are replaced by Tahuampa in Amazonian Peru. This paper attempts to define the major inundated forest types of importance to plant ecologists and systematists. Seven main types of periodically or permanently flooded forest are important for vegetation studies of Amazonia: 1-5 Periodically inundated types. 1. Seasonal várzea — white water forest flooded by regular annual cycles of rivers. 2. Seasonal igapó — black and clear water flooded by regular annual cycles of rivers. 3. Mangrove — twice daily tidal flooding by salt water. 4. Tidal várzea — twice daily tidal flooding by back up of fresh water. 5. Flood plain forest — low lying ground flooded by irregular rainfall, generally in upper reaches of rivers. 6 - 7 Permanently waterlopped — Permanent swamp forest 6. Permanent white water swamp forest. 7. Permanent igapó (Black water) There are certainly many subdivisions of these seven major categories but there are insufficient phytosociological data to subdivide them meaningfully at this stage. This terminology restricts the use of igapó to black and clear water situations as has been done by limnologists for many years.