Abstract
A monoclade Sphagnum was found on the Azorean island of Terceira. It resembles much S. pylaisii in appearance, and has been recorded under this name from this locality, but differs by the position of the chlorocysts in transverse section of the leaves. With regard to the position of chlorocysts, it has to be included in sect. Subsecunda. In fact, the plants grew together with S. denticulatum. To test, whether the monoclade plants belong to S. denticulatum, the Internal Transcribed Spacer (ITS) 1/2 regions of nrDNA of the normal and monoclade expressions was sequenced. It turned out that both show almost no differences (except for two deletions) and thus belong to the same species. The monoclade expression of S. denticulatum is interpreted as somatic mutation of the latter and described here as new variety.
In connection with this study, the type of Sphagnum monocladum Warnst. was examined. It is not monoclade as the name suggests but irregularly branched. The type belongs definitely to the sect. Cuspidata as originally attributed by Warnstorf and not to sect. Subsecunda as suggested by Paul.