Taxonomic Revision and Conservation Status of the Species of Eryngium (Apiaceae, Saniculoideae) Native to Australia

Abstract

The “Pacific” clade of Eryngium L. is a group comprising ca. 40 species that grow in Australia, Chile, the western United States, and east-central South America. Taxonomic studies of the American lineages of this clade have recently been published. However, the Australian species of Eryngium have not been taxonomically revised for more than a century. The objective of this study was a taxonomic revision of the Eryngium species native to Australia, including an analysis of their conservation status. For this, the morphology, geographic distribution, and habitat of ca. 550 herbarium specimens were analyzed. In addition, the conservation status of each species was informally evaluated following the IUCN Red List categories and criteria of the International Union for Conservation of Nature. In total, nine Eryngium species native to Australia are recognized, eight of which are endemic. A key for the recognition of these species is provided. For each species, a list of accepted synonyms, a morphological description, an illustration, a distribution map, and a discussion of habitats are presented. Two new synonyms are proposed, a new combination is presented, and nomenclatural problems are analyzed and resolved, including the typification of seven names. The morphological analyses of this study show that the majority of Eryngium species from Australia are heterophyllous. This characteristic had been reported previously for only two Australian Eryngium species. Two of the nine Australian species of Eryngium were found to be in a threatened category.