Phytoliths in modern plants from Amazonia and the Neotropics at large. II Enhancement of eudicotyledon reference collections

Phytolith studies of Neotropical vegetation history and its human influences require large modern reference collections from diverse woody and herbaceous plants. In order to further enlarge our reference collection, we analyzed phytoliths from 435 species of eudicotyledons from 84 families and 361 genera of mainly lowland Amazonian forest taxa along with other Neotropical plants. Our analysis revealed new morphologies from the silicification of bark in arboreal taxa that don't produce diagnostic vegetative phytoliths, as well as distinctive-looking phytoliths from leaves of previously unstudied trees. Several of the phytolith types uncovered here occur as unknowns in our earlier Amazonian terrestrial soil research. No morphotypes were revealed that overlapped with diagnostic phytoliths documented previously in other families and genera. Our reference collection now totals approximately 1540 Neotropical eudicotyledon species. For the Amazonian forest below 1000m it includes 80% of eudicotyledon families often with half or more of their genera and many of the most commonly occurring trees. A significant number of herbaceous and arboreal/woody taxa can be identified at the family, genus, and possibly species level for study of Neotropical vegetational and forest history. Phytolith and palynological investigations are excellent complements to each other.