First records of Dryopteris ×bra­thaica Fraser-Jenk. & Reichst. (Dryopteridaceae, Pteridophyta) in South Germany – morphological and molecular studies

Abstract

During botanical mappings from 2001 to 2011 six plants of the rare hybrid D. ×brathaica (D. carthusiana × D. filix-mas) were discovered in the alpine foothills of Baden-Württemberg and the adjacent Bavarian Allgäu. Molecular genetic studies on different Central European species of the genus Dryopteris have revealed length-polymorphisms in fragments of the PgiC gene (cytosolic Phosphoglucose-isomerase), characteristic of some species. These polymorphisms are shown by electropherograms of the taxa involved. The derivation of the two hybrids D. ×brathaica and D. ×deweveri (D. dilatata × D. filix-mas) was affirmed by molecular genetic analysis. A retrospective view of previous reports on D. ×brathaica is followed by a description of the localities of the new discoveries, some aspects of the taxon’s ecology and accompanying ferns. A detailed morphological description is provided based on the plants from Baden-Württemberg and Bavaria as well as on herbarium fronds of the plants originating from England and Austria. The morphologically intermediate position of the hybrid between its parental species is illustrated by various characteristics and morphometric measures. Its distinctiveness from D. remota is demonstrated. A chromosome count was carried out for one of the newly recorded plants