I used a nearly complete phylogenetic tree for Viburnum (Adoxaceae) to analyze the evolution of 20+ conspicuous morphological traits. These show various levels of homoplasy, from none at all (e.g., extrafloral nectaries, panicle inflorescences) to >20 inferred state changes (leaf teeth, leafing behavior). Most traits are in a range from 2-10 shifts, including tri-lobed leaves, naked buds, sterile marginal flowers, pollen exine sculpture, stipules, ruminant endosperm, corolla tubes, and fruit colors. There are several striking phylogenetic correlations. For example, toothed leaves are strongly correlated with the deciduous habit, both having evolved in response to colder and more seasonal climates. Other correlations arise from one character likely promoting the evolution of another character to provide a particular function. For example, tuft domatia have originated multiple times in the major lineage characterized by extrafloral nectaries, apparently to enhance protection by leaf mites. Likewise, shifts to derived branching architectures appear to have promoted the evolution of sterile marginal flowers, which increase pollinator visitation and fruit set. The independent origins of several fruit syndromes has entailed the coordinated evolution of fruit color and size, mesocarp texture, endocarp shape, and chemistry. Other cases of phylogenetic clustering are less clearly related to function. Stipules have evolved in the context of trilacunar nodal anatomy and lobed or toothed leaves. Here, developmental studies in Viburnum are consistent with the view that stipules are non-functional appendages homologous to leaf lobes or teeth that are initiated very late in the basipetally developing leaf. This case, and several others (tri-lobed leaves, yellow fruits), provide prime examples of what persecuted Russian geneticist, Nikolai Vavilov, termed “the law of homologous series in variation” — the recurrence of particular variants in closely related plants underlain by structures and developmental processes that promote their repeated emergence. Two other general findings are noteworthy. First, there are no clear cases of morphological “key innovations” in Viburnum, either in the sense of opening up a new adaptive zone or enhancing diversification. Instead, shifts in diversification rate appear mostly to have been promoted by the occupation of mountainous regions. Second, morphological traits are not misleading with respect to Viburnum phylogeny. Indeed, they collectively yield results that match those based on molecular data, though with less resolution. Changes in multiple characters provide unequivocal support for many major clades, especially for the small early-branching Pseudotinus, Tinus, and Opulus lineages. In the few cases where chloroplast and nuclear data conflict, morphological traits are more consistent with the nuclear data.