To clarify relationships within the predominantly Neotropical and exclusively fleshy‐fruited Myrteae (49 genera and c. 2,500 species), we provide a phylogenetic hypothesis for evolutionary relationships between 31 of these genera by analyzing nuclear ITS and ETS ribosomal DNA, and plastid psbA‐trnH and matK DNA sequences from 75 Myrteae species and 13 outgroup taxa using parsimony and Bayesian inference. Four morphological characters are epitomized on the resulting trees, and biogeographical analyses are also performed. Myrteae are monophyletic, comprising seven clades plus two isolated taxa of unclear relationships. Morphological characters exhibit homoplasy, although in combination are useful for clade diagnosis. Biogeographical analyses are inconclusive regarding the ancestral area of the tribe, but South American colonization before northern radiation via the Andes appears likely. The largest genera, Eugenia and Myrcia s.l., have western and southeastern South American origins, respectively.

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Floral organogeny and stamen development are described for three species of New Zealand Myrtoideae not examined previously: Lophomyrtus bullata, L. obcordata, and Neomyrtus pedunculata. The flowers have numerous stamens, which are initiated on the flank of an invaginated floral apex. The stamen primordia are initiated relatively early after petal initiation and continue to initiate on the flank until all of the space is occupied. The hypanthium has a critical role in the development of antesepalous stamens and their direction of growth in the mature flower. The hypanthium also has a role in the final position of the petals and sepals in the mature flower. This work supports the current view that floral architecture in the Myrtaceae is the result of timing and duration of stamen initiation and the enlargement of the hypanthium. This is the first in-depth study of floral development in fleshy-fruited Myrtaceae.

Floral organogeny and development are described for three species of South American Myrtoideae: Acca sellowiana, Luma apiculata, and Ugni molinae. The flowers have large numbers of stamens which vary in size but are all initiated on the flank of the invaginated apex. The floral architecture is the result of the degree of synchrony of the timing of stamen initiation and hypanthial expansion. In A. sellowiana and U. molinae, stamen initiation is synchronised with hypanthial expansion, resulting in the even distribution of stamens over the entire hypanthial surface. Stamens of L. apiculata are initiated during and after hypanthial expansion, resulting in a discontinuous ring of stamens at the periphery of the hypanthium. Development in these species is in contrast to New Zealand Myrtoideae, where stamen initiation is complete prior to the completion of hypanthial expansion, resulting in the inner-most stamens forming a discontinuous ring.

Floral organogeny and development are described for two species of the Acmena alliance: Acmena smithii and Syzygium australe. The Acmena alliance is now regarded as distinct from the fleshy-fruited Myrtoideae s.s. A. smithii develops an hypanthium that resembles that seen in some dry-fruited Myrtaceae but stamen initiation resembles that seen in the fleshy-fruited Luma apiculata. By contrast S. australe has hypanthial development similar to the New Zealand fleshy-fruited Myrtaceae but stamen development resembles that of many dry-fruited Myrtaceae. Both species, therefore, show homoplasy of floral characters with both fleshy and dry-fruited Myrtaceae.