Three newly reported escaped non-native Costus L. species (Costaceae) in Java, Indonesia

Abstract

Costus L. is the most species-rich genus in Costaceae and is mainly distributed in the Neotropics and tropical Africa. Five Costus species have been introduced to Java, Indonesia, for ornamental purpos-es. During our botanical expeditions in Java from January to May 2023, we discovered three previously unreported species of Costus that occur spontaneously in the wild: C. phyllocephalus K.Schum., C. spicatus (Jacq.) Sw., and C. villosissimus Jacq. Their spontaneous populations have been found on roadsides and abandoned areas in West Java.