Notes on Pachyphyllinae (Vandoideae, Orchidaceae) with a description of a new genus

The Neotropical subtribe Pachyphyllinae comprises orchids distributed mainly along the Andes and characterized by the monopodial type of growth. The systematic position of this taxon within Orchidaceae and its generic composition was intensively discussed, but so far no comprehensive morphological study on the group was conducted. In this paper the morphological descriptions of all genera included in Pachyphyllinae are provided and the key to their identification is presented. In addition, the taxonomic position of Raycadenco is discussed. The research revealed the existence of two distinctive species which were classified until now within Pachyphyllum or Fernandezia. Since neither the flower morphology of those two species nor the gynostemium structure fulfils the concept of any known orchid taxon, the new genus is described here under the name Valdiviesoa. The two representatives of the new taxon are illustrated and the photographs of the plants are provided. The information about their distribution and ecology are provided. The morphological characters of all Pachyphyllinae representatives are compared.