Phylogenetic tree of the selected plant species. Branch lengths are approximate. Grey text indicates species that will not be sampled (shown for reference only) or for which small RNA data are already available or underway. Asterisks indicate whole genome sequences are available or underway (admittedly, an incomplete list). The gymnosperm and angiosperm clades are modified from the floral genome project; the lower plant phylogeny is modified from Blue boxes indicate the families on which we are focused.