Abstract:

Phylogenetic stemminess is one of the most popular metrics of tree shape among evolutionary biologists. The index was originally described by Fiala & Sokal (1985) as the proportion of the total length of the branches of a phylogenetic clade (including the subtending branch or “stem”) that is accounted for by the length of the subtending branch of the clade. Accordingly, phylogenies with high stemminess would show accumulation of speciation events toward the present, whereas those with low‐stemminess values would reflect the opposite pattern (i.e., speciation events skewed toward the root node, Fig. 1).