Varzea forest areas are inaccessible except by small boat for several months of the year, and are floristically depauperate in comparison to terra firme forest areas. Varzea plant communities are very distinct from upland plant communities, however, being adapted to survive annual floods that can last for several months. Some varzea plant species can be totally submerged in virtual blackness for several months and still survive. Along trails in both varzea and terra firme forest at Madre Selva, a number of plant species have been identified and labeled to assist visitors in learning some of the commoner species. The understory flora of all three sites is particularly rich in palms, rubes, melastomes, ferns, aroids and broad-leaved monocots.
Palms are also very notable components of the midstory and canopy level.
A large number of other 'ant-plant' species also occur at the field sites. Plant lists of some of the more conspicuous and common species at the field sites are currently being developed.