Palynology of Huberia (Melastomataceae: Cambessedesieae): diversity and taxonomic implications

Abstract

Huberia DC. is a genus belonging to the family Melastomataceae, which comprises 37 species distributed in vegetation formations of the Amazon Forest and Andes complex and the Atlantic Forest biome. Recent phylogenetic studies have modified the circumscription of the genus to include the genera Behuria Cham. and Dolichoura Brade. Furthermore, the genus was placed in the new tribe Cambessedesieae, together with the genera Cambessedesia DC. and Merianthera Kuhlm. In view of the relevant contribution of palynology to taxonomic and phylogenetic studies, this study aimed to expand the palynological knowledge of Huberia. Samples from 22 species were obtained from specimens deposited in the herbaria of the Rio de Janeiro Botanical Garden (RB), National Museum/UFRJ (R), Municipal Botanical Museum of Curitiba (MBM), and Federal University of Paraná (UPCB). Flower buds were acetolysed and used to prepare pollen sediment slides. Slides were mounted with glycerinated gelatin and analyzed and photographed under a light microscope. The results showed pollen grains in monads, small, varying in shape from prolate-spheroidal to subprolate; heteroaperturate (colporate and pseudocolpate), tricolporate, with a small, very small, or non-existent polar area in syncolporate pollen; colpi long or very long and narrow, endoaperture lalongate with median constriction in most species and lolongate in others; exine perforate, rugulate, or striate microreticulate and the sexine thicker than the nexine. Based on the findings of this study, it is concluded that palynological characters provide information for the taxonomy of the group.

Keywords:

• Atlantic Forest
• Behuria
• Dolichoura
• palynotaxonomy
• pollen

Acknowledgements

We also thank the herbarium curators for providing access to their collections and the Scanning Microscopy Laboratory, National Museum, Federal University of Rio de Janeiro, Brazil, for conducting the analyses.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Data availability statement

All data supporting the findings of this study are available from the corresponding author.

Additional information

Funding

V. Gonçalves-Esteves and C. B. F. Mendonça are grateful to the Brazilian National Council for Scientific and Technological Development (CNPq) for the research grants (grant Nos. 304910/2019-8 and 31618/2021-9). All authors thank the Rio de Janeiro State Research Foundation (FAPERJ) (grant Nos. 26.0003/015254/2021 and E-26-/203.007/2017). We are grateful to the Brazilian Federal Agency for Support and Evaluation of Graduate Education (CAPES) and the Post-Graduate Support Program (PROAP) for awarding scholarships.