Data from: Leaf form evolution in Viburnum parallels variation within individual plants

Few studies have critically evaluated how morphological variation within
individual organisms corresponds to variation within and among species.
Sub-individual variation in plants facilitates such studies because their
indeterminate, modular growth generates multiple serially homologous
structures along growing axes. Focusing on leaf form, we evaluate how
sub-individual trait variation relates to leaf evolution across Viburnum,
a clade of woody angiosperms. In Viburnum we infer multiple independent
origins of wide/lobed leaves with toothed margins from ancestors with
elliptical, smooth-margined leaves. We document leaf variation along the
branches of individual plants of 28 species and among populations across
the wide range of V. dentatum. We conclude that when novel leaf forms
evolved in Viburnum, they were intercalated at the beginning of the
seasonal leaf sequence, which then generated a repeated spectrum of leaf
forms along each branch (seasonal heteroblasty). We hypothesize that the
existence of such a spectrum then facilitated additional evolutionary
shifts, including reversions to more ancestral forms. We argue that the
recurrent production of alternative phenotypes provides opportunities to
canalize the production of particular forms, and that this phenomenon has
played an important role in generating macro-scale patterns.