Evolution of Endocarp Morphology and Implications for Seed Dispersal in Viburnum (Adoxaceae)

Abstract

Viburnum comprises ~165 shrubs and small trees with fleshy fruits typically dispersed by birds. Viburnum fruits are drupes, which are fleshy, indehiscent, and contain a single seed with a tiny embryo. The endocarp (hard inner wall of the ovary) varies considerably in shape and size across the clade, and endocarp characteristics have long been used to identify major subgroups within Viburnum. Prior study of endocarp evolution used a 40 species phylogeny that did not represent all currently recognized groups of Viburnum1. We have quantified variation in endocarp shape and have traced the evolution of endocarp morphology using an expanded Viburnum phylogeny2,3. We now recover multiple instances of convergent evolution among endocarp shape, that suggests various evolutionary strategies for fruit and seed dispersal