Rubus silvae-norticae, a new species from Bohemia, Austria and Bavaria and the significance of brambles for regional migrations.

A new bramble species, Rubus silvae-norticae, section Rubus, subsection Hiemales E. H. L. Krause in Prahl, series Micantes Sudre, which occurs in S Bohemia, Upper Austria and Lower Bavaria, is described. It is recorded at 130 localities. The distance between the most remote localities is ca 100 km. The species grows most frequently in forest habitats (as a distinctly nemophilous ecoelement) such as ditches and edges of forest roads, plantations, forest margins and clearings. It mainly grows in mesic, acid and mineral-poor soils. Like, for example, R. clusii or R. ser. Glandulosi and unlike other relatively thermophilous Rubus species, it is able to grow and propagate itself at rather high altitudes, up to the mountain vegetation belt. The diagnostic characters that separate R. silvae-norticae from its most similar and sympatrically occurring species, R. clusii and R. muhelicus, are provided. In Austria R. silvae-norticae and some other brambles were mistakenly considered as R. helveticus, a bramble (probably a single biotype) described from Switzerland in 1870. The lectotype of Rubus helveticus is designated here and a photograph of the specimen presented. Also included is a distribution map of R. silvae-norticae, a list of revised herbarium specimens, a photograph of the type specimen and a pen drawing of the species. The significance of regional brambles for plant migrations and phytogeography is shown, based on the distribution of selected regional Rubus species occurring in the Czech and Austrian border area, which is a known mountain barrier to migration. The distribution patterns of the brambles support a theory about the routes of plant migration and the florogenetic connection between Austria and the Czech Republic. Rubus silvae-norticae, R. muhelicus and R. vestitus f. albiflorus are regarded as Danubian migrants (distributed from Upper Austria to S Bohemia), whereas R. gothicus s. l. (“south Moravian type”) and R. austromoravicus are considered to be Dyje-Kamp migrants (distributed from Moravia and Lower Austria to S Bohemia) within the Bohemian flora. Rubus kletensis is supposed to be a Vltava migrant within the Austrian flora (distributed from S Bohemia to Upper Austria).