Synonymizing Two Species Names, Designating Lectotypes, and Cataloging Intermediates in Two Hybrid Zones of Hedychium

Abstract

Hedychium J. Koenig (ginger lilies: Zingiberaceae), a genus known for its ornamental value and invasive potential, is undoubtedly a taxonomically challenging genus within Zingiberaceae. Much of the confusion surrounding the taxonomy of Hedychium arises from the introduction of redundant names for the same taxa in various regions of the Indo-Malayan Realm, which has led to a proliferation of synonyms that remain insufficiently explored. Additionally, taxonomic confusion in this genus is also due to the occurrence of numerous natural hybrids and polyploids. In this article, we propose that H. peregrinum N. E. Br. from Madagascar is a synonym of H. roxburghii Blume, and H. sinoaureum Stapf from China is a synonym of H. densiflorum Wall. Additionally, we lectotypify three of these species names. We also identify and characterize two natural hybrid zones of Hedychium from the northeastern states of India. Further, we highlight the importance of naming intermediate taxa or natural hybrids, and propose a curated online repository for Hedychium (including valid species and hybrids), aided by citizen science, which will help us digitally collate information on polymorphism, morphological diversity, and geographic variations within the genus.