Weeding the nettles VI: Taxonomic and phylogenetic studies of the Southeast Asian Urtica fissa-clade (Urticaceae)

Abstract

Urtica L. (Urticaceae) is a subcosmopolitan genus common throughout temperate Asia. Species delimitation is very difficult and the present study investigates a group of taxa associated with Urtica fissa from East-Southeast Asia and based mainly on herbarium collections, including most of the type specimens and cultivated plants. Species limits especially of U. mairei, U. fissa and U. himalayensis have been consistently confused in both herbaria and floristic treatments. As part of a taxonomic revision we produced a molecular phylogeny of the group based on ITS1-5.8S-ITS2, psbA–trnH, trnL–trnF and trnS–trnG markers. Our revision recovers a total of five species and two subspecies: U. fissa E.Pritz. ex Diels, U. grandidentata Miq. subsp. grandidentata, U. grandidentata Miq. subsp. lombok K.Becker & Weigend, U. himalayensis Kunth & C.D.Boché, U. mairei Lév. and U. parviflora Roxb. We provide type information, diagnostic characters, a key to species identification, species conservation assessments and a list of exsiccatae for each taxon.