Pollen morphology of the South American genus Lessingianthus (Vernonieae, Asteraceae) and its taxonomic implications

Abstract

The pollen grains of 111 species of Lessingianthus were analysed. Almost all the species belong to the type “B” pollen, characteristic of the genus. These grains are oblate-spheroidal, spheroidal to prolate-spheroidal (P/E 0.93–1.04), echinolophate, 3-colporate, with lacunae in a regular pattern, without polar lacunae. However, some species show variations of this basic type. The type “B-1”, “B-2” and “B-3” grains are respectively 3-porate lacking equatorial lacunae, 3-porate with equatorial lacunae and 3-colporate, psilolophate. Also, one species showed type “D” pollen, a palynomorph present in other genera of the tribe but not reported until now for Lessingianthus. The analysis confirms that the species of the genus constitute well-defined groups based on the pollen characteristics. The results ascertain that pollen morphology is a significant feature in the identification and delimitation of species and genera of Vernonieae.

Keywords:

• Taxonomy
• classification
• Vernonia
• Compositae

Acknowledgements

This work has been supported by grants from the Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET) and the Secretaría General de Ciencia y Técnica of the Universidad Nacional del Nordeste, which are greatly appreciated.

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