The genus Betula (birches) is widely distributed in the northern hemisphere from the arctic to the tropics. Its woody species are an important component of many ecosystems, and of economic value. The genus was recently subjected to taxonomic revision in a monograph by Ashburner and McAllister (Kew Press, 2013).
Wang et al. provide a phylogenetic tree and genome size measurements for living collections of Betula collected and curated by the monograph authors. This allows assessment of the higher level taxonomic groupings of the genus, and of previously published GenBank accessions of Betula species.