Abstract

Based on molecular results, several Opegrapha species have been assigned to other genera. The aim of this study was to investigate if there are differences in excipulum structure between Alyxoria, Opegrapha and Zwackhia. Microscopic examination of the excipulum of Alyxoria culmigena, A. ochrocheila, A. varia, Opegrapha vulgata, Zwackhia sorediifera and Z. viridis was performed on 3-5μm thick sections. Small portions of the ascomata were frozen in water and cut with a freezing microtome. The sections were incubated with NaOCl (chlorine 1:10), and the progressive dissolution of the dark excipulum pigmentation was photographed continuously using a light microscope. Maximum dissolution time was about 50min. A computer-generated contrast enhancement of the hyphal walls was made with Adobe Photoshop. The molecular data concerning the distinction of the genera Alyxoria and Zwackhia could be supported by morphological differences. The excipulum hyphae of Alyxoria originate from the hypothecium while in Zwackhia they apparently originate from a layer below the hypothecium. Thus, our results indicate that excipulum structures can be used to distinguish these genera. For the morphological differentiation of Opegrapha vulgata and Alyxoria spp. more investigation is required.

Published in

Publisher: Svenska systematikföreningen

Conference

Systematikdagarna 2016, 21-22 november, Uppsala.

SLU Authors

• Hillman, George

  • Department of Ecology, Swedish University of Agricultural Sciences
    

• Thor, Göran

  • Department of Ecology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Botany


Permanent link to this page (URI)

https://res.slu.se/id/publ/80198