A new species of Succisa (Caprifoliaceae, Dipsacoideae) from Southwestern Portugal

Abstract

The Portuguese Southwestern Ranges, including Serra do Cercal and Serra da Brejeira, are an understudied centre of plant endemism. This region experienced rapid landscape transformation, due to eucalyptus plantations, before thorough botanical exploration could be conducted. Here, we describe Succisa brevipedunculata, a newly identified narrow endemic restricted to rocky acid siliceous soils between Odemira and Aljezur. Additionally, we report the common occurrence of false viviparity in this taxonomic novelty, a little-known phenomenon in dipsacoids. Distinguished by its relatively short primary pedicels and long leaves, S. brevipedunculata corresponds to plants previously identified as S. pinnatifida in southern Portugal, and is preliminarily assessed as globally Endangered according to the IUCN Red List criteria. Conversely, S. pinnatifida is re-evaluated as a Near Threatened Northwest Iberian endemic, reaching Beira Litoral to the south. The two species probably form a monophyletic group that evolved in rocky scrubland, and both are endemic to the western margin of the Iberian Variscan Belt. This study provides a taxonomic treatment for this clade including an identification key for Succisa in the Western Palearctic, and accounts on species ecology, including biotic interactions involving S. brevipedunculata, and conservation assessments.