Rubus atroroseus (Rosaceae), a new species of the section Corylifolii from the Czech Republic

A new tetraploid bramble species, Rubus atroroseus, classified within the subgenus Rubus, section Corylifolii, series Sepincola, is described. It is a regional species endemic to north-western Bohemia. It has been recorded at ca 70 localities and the distance between the most remote localities is ca 60 km. It grows most frequently in open and sunny habitats such as roadside ditches, open scrub and fringes of meadows, scrub, and woodlands. The morphological variability of the species is low and indicates apomixis as the probable dominant mode of its reproduction. Rubus atroroseus differs distinctly from all related species known from the Czech Republic and adjacent Germany by the following characters: primocanes pruinose, intensively suffused dark brown-red (in sunlit sites), sparsely hairy and glandular, primocane leaves deep green above, terminal leaflet of primocane leaves usually round with a double serrate margin, pedicels with usually 1-2 prickles, and petals deep pink. A distribution map, a list of revised herbarium specimens, a photograph of the type specimen, a pen drawing and in situ photographs of the species are provided.