Diversity and distribution of Myristicaceae in the Amazonian State of Acre, Brazil

The family Myristicaceae (Magnoliales) comprises ca. 500 species and has a pantropical distribution and centres of diversity in Africa, Asia and the Neotropics. In the latter, the Amazon Region, the largest rainforest in the world, is notable for having about 65 Myristicaceae species and recorded hyperdominance with 29 species of five genera, with a highlight for Iryanthera Warb. and Virola Aubl. genera with 13 and 11 hyperdominant species, respectively. Although the Amazon is known to be highly biodiverse, with 14,003 known seed plant species, much remains unknown due to the lack of proper research funding and difficulty in accessing many areas. This study aims to increase our knowledge of the family and the region by providing curated data about the occurrence of Myristicaceae species in the Amazonian State of Acre in Brazil.

We provide a dataset with 34 species and five genera of Myristicaceae recorded in Acre, Brazil, treated in the most recent flora by the authors. This includes the nine new occurrences for the State and corresponds to ~ 31% of the family's species richness in the American continent. The distributions exhibit different patterns, with 16 species found throughout the State and 18 species restricted to one of two watersheds. This difference between the diversity in the two basins was previously observed in other studies of birds and vines and here which we observed may also be the case for trees and treelets. We also observed the ratio of staminate and pistillate inflorescences amongst the collections, with a staminate-biased ratio of approximately 7:1.