Are there Lichenized Ostropales?

Abstract

Ostropales, in a wide sense, currently encompasses Ostropales s. str., with a few lichenized genera, and Graphidales, most of which are lichenized. Conotrema is the only lichenized genus undoubtedly placed in Ostropales s. str. We have sequenced the 18S rRNA gene from some key taxa to answer the questions as to whether one ortwo orders should be recognized and whether Conotrema should be kept in Ostropales if Graphidales is recognized. We have new sequences from Conotrema populorum (Stictidaceae, Ostropales), Cyanodermella viridula (Stictidaceae Ostropales), Graphis scripta (Graphidaceae Graphidales) and Diploschistes ocellatus var. almeriensis (Thelotremataceae Graphidales). In an analysis with 41 taxa, thelichenized D. ocellatus var. almeriensis and G. scripta are the sister group of the lichenized C. populorum and the non-lichenized C. viridula and Stictis radiata. Together they form a monophyletic cluster supported by a bootstrap value of 82%. Therefore, it is possible to use the ordinal name Ostropales in a wide sense to include the Graphidales. If Ostropales are conceived in a narrow sense, Conotrema should be kept in the Stictidaceae. Eight new PCR primer sequences are reported.