Inflorescence and floral morphology of Haptanthus hazlettii (Buxaceae, Buxales)

Author(s)
Alexei Oskolski, Anna Maria Louise von Balthazar-Schönenberger, Yannick Städler, Alexey B. Shipunov
Abstract

The enigmatic Central American tree Haptanthus hazlettii has recently been placed in Buxaceae (Buxales) by molecular evidence. However, Haptanthus appears morphologically to be fundamentally different from other Buxales in having pluriovular carpels with parietal placentation and reduced male reproductive units of an obscure morphological nature. The latter have been interpreted to be pairs of unistaminate flowers, or single flowers, either bearing two stamens or a pair of phyllomes with adnate introrse anthers. We (re-)investigated the structure of the inflorescences and flowers of Haptanthus in order to clarify their homologies with reproductive structures of Buxales. We found that, despite some distinctive traits of flower morphology, Haptanthus shares many floral characters, including the opposite and pairwise arrangement of floral organs and the fusion between perianth members and stamens, with some Buxales and other early-branching eudicots. The plicate and pluriovular gynoecium of Haptanthus may be the result of a drastic elongation of the symplicate zone, accompanied by an increase in ovule number, and is thus a derived trait in Buxales. The anther-bearing structures are phyllomes with adnate anthers rather than stamens or unistaminate flowers.

Organisation(s)
Department of Botany and Biodiversity Research
External organisation(s)
University of Johannesburg (UJ), Russian Academy of Sciences, Minot State University
Journal
Botanical Journal of the Linnean Society
Volume
179
Pages
190-200
No. of pages
11
ISSN
0024-4074
DOI
https://doi.org/10.1111/boj.12303
Publication date
09-2015
Peer reviewed
Yes
Austrian Fields of Science 2012
106008 Botany, 106042 Systematic botany, 106012 Evolutionary research
Keywords
ASJC Scopus subject areas
Ecology, Evolution, Behavior and Systematics, Plant Science
Portal url
https://ucrisportal.univie.ac.at/en/publications/75e31d4d-e84f-4ec7-8d15-1e958b3eb1ad