Development of the hypanthium and androecium in South American Myrtoideae (Myrtaceae)

Abstract

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. © 2003 Taylor & Francis Group, LLC.