Pollen morphology of columnar cacti from Tehuacán-Cuicatlán Valley, Mexico

Abstract

The most important centre of diversity and endemism of columnar cacti in Mexico is the Tehuacán-Cuicatlán Valley (Puebla-Oaxaca states). The aims of this paper are (1) to provide a detailed description of the recent pollen morphology of 19 registered species that are found in this valley and (2) to develop a synoptic table to differentiate groups of species. This synoptic table is based on morphological features of pollen grains and the density of structural and sculptural elements observed using light and scanning electron microscopy. All analysed pollen grains were stenopalynous: isopolar monads, large, tricolpate with perforate tectate exine (sexine-nexine ratio 1:1), columellate structure with pattern of columellae distribution and spinulose sculpture. The spinules were always wider than they were tall. Although the 19 species of columnar cacti analysed in this study show highly similar types of pollen grains, we were able to characterise each of them with combined microscopy techniques.

Keywords:

• Pollen morphology
• columnar cacti
• Tehuacán-Cuicatlán Valley
• Mexico

Acknowledgments

The authors wish to acknowledge the valuable recommendations made by the reviewers and editor. We thank Dr. David Sebastian Gernant for his authorisation of the sampling of MEXU collection specimens, M.Sc. Alberto Reyes García for his support in selective anther sampling of MEXU and also acknowledge professor Luis Felipe Jiménez-García from Departamento de Biología Celular, Facultad de Ciencias, Universidad Nacional Autónoma de México. We also wish to thank both Patrick Bennett Weill for the revision of the English version and Dr. Rocío Castillo Aja from the University of Guadalajara who made the map. This research was supported by PAPIIT-DGAPA IN-116523, Universidad Nacional Autónoma de México.

Disclosure statement

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