Pollen morphology of the Amacayacu Forest dynamics plot, Western Amazon, Colombia

Amacayacu Forest Dynamics Plot (AFDP) is a 25-ha (500 m × 500 m) site located at Amacayacu National Natural Park (ANNP), Colombian Amazonia. The flora of AFDP is represented by terra firme Forest, the phytophysiognomic unit of the Amazon region with the greatest richness of plant species. However, high-resolution pollen images and morphological descriptions from the Amazon North-west are still rare. This study presents detailed information about pollen grains that will benefit future palynological analyses, particularly of Quaternary material. Herein we describe 255 tree species, comprising 72 families and 192 genera. Those species were grouped into 236 morphotypes. Six species revealed morphological variations among the pollen types within the same species and 36 species were impossible to differentiate from each other. Overall morphology shows apertures with a dominance of tricolporate (61%), inaperturate (5.8%), monocolpate (5.5%), and triporate (4.7%), and variation of sexine sculptures, with dominance of reticulate (66%), scabrate (11.3%), echinate (7.05%) and rugulate (4.3%). With respect to size, the equatorial diameter has a median of 29 µm (SD = 15.5), while the polar diameter has median of 32 µm (SD = 14.7).