Vincetoxicum samothracicum (Apocynaceae), a new species from Mt. Saos, Samothraki Island, Greece

Samothraki, an island of the North Aegean region of Greece, hosts a remarkable flora that includes seventeen endemics restricted to its boundaries and several species of phytogeographical importance. A floristic investigation of the upper parts of the island, on Mt. Saos, revealed populations of a reddish-purple-flowered Vincetoxicum morphologically distinct from any species known from Greece and neighboring countries. This new species, named Vincetoxicum samothracicum, is apparently related to a group of east-Mediterranean species with corona lobes free almost to the base, but it differs from all of them in the characters of the flowers, fruits, and indumentum. Investigation of an internal transcribed spacer (ITS) Vincetoxicum phylogeny did not place the new species in the same monophyletic group as its presumed morphological relatives. V. samothracicum is a local species, but it is currently assigned to the IUCN category LC.