The identity of Plagiostachys parviflora (Zingiberaceae: Alpinioideae) unravelled after 196 years

Abstract

We collected specimens in Ilocos Norte, Philippines, and identified them as Plagiostachys parviflora (C.Presl) Ridl. (Zingiberaceae: Alpinioideae), a species of which the identity remains doubtful since its publication in 1827. This is one of the ginger species described and illustrated by Carl Presl using Thaddäus Haenke’s specimen collected in the Philippines during the Malaspina expedition. The description of Plagiostachys parviflora is expanded here based on new collections including pickled fertile material, and the species is illustrated by a colour plate. Notes on its distribution, phenology, local names, and other notes are also given. Amomum parviflorum C.Presl var. bifidum C.Presl and Plagiostachys rolfei (K.Schum.) Ridl. are treated here as synonyms of P. parviflora. Lectotypes are designated for Amomum parviflorum, Amomum parviflorum var. bifidum, and Alpinia rolfei K.Schum., and their respective type localities are discussed. Plagiostachys parviflora matched the criteria of the IUCN Red List to be considered as Vulnerable (VU). An updated key to the Philippine species of Plagiostachys is also provided.