A peer-reviewed open-access journal PhytoKeys 158: 1–106 (2020) Taxonomic revision of Xenophyllum 1 doi: 10.3897/phytokeys.158.50848 MONOGRAPH http://phytokeys.pensoft.net Launched to accelerate biodiversity research Taxonomic revision of the Andean genus Xenophyllum (Compositae, Senecioneae) Joel Calvo1, Andrés Moreira-Muñoz1 1 Instituto de Geografía, Facultad de Ciencias del Mar y Geografía, Pontificia Universidad Católica de Valpa- raíso, Avenida Brasil 2241, 2362807 Valparaíso, Chile Corresponding author: Joel Calvo (
[email protected]) Academic editor: A.R. Magee | Received 5 February 2020 | Accepted 1 July 2020 | Published 3 September 2020 Citation: Calvo J, Moreira-Muñoz A (2020) Taxonomic revision of the Andean genus Xenophyllum (Compositae, Senecioneae). PhytoKeys 158: 1–106. https://doi.org/10.3897/phytokeys.158.50848 Abstract The Andean genusXenophyllum (Compositae, Senecioneae) is distributed along the high-Andes from northeastern Colombia to northern Chile and northwestern Argentina, mainly thriving in the paramo and puna ecoregions. It comprises suffruticose plants forming dense mats, hummocks, or clumps of erect stems. They are characterized by displaying involucral bracts fused at the base, supplementary bracts ab- sent, and mostly radiate capitula with white ray corollas, seldom yellow or pink (disciform in one species). Traditionally, Xenophyllum species were treated as members of the genus Werneria, a morphologically close genus that includes rosettiform or scapiform perennial herbs. As currently circumscribed, Xenophyl- lum mostly differs from Werneria in having elongate stems. Herein, the first modern and comprehensive revision of the genus recognizing twenty-two species and two subspecies is presented. Werneria decumbens is synonymized with X. weddellii, as well as X. fontii with X.