A global synthesis of diversity, taxonomy, and phylogeny in Allium (Amaryllidaceae)
Abstract
ABSTRACT The genus Allium (Amaryllidaceae) is one of the most taxonomically complex and mega-diverse genera in the Northern Hemisphere. Despite its ecological and economic importance, its global diversity, checklist, phylogeny and taxonomy, including infrageneric classification, remain incompletely resolved. Here, we provide a comprehensive global checklist of Allium , including species, sections and subgenera, together with an assessment of global diversity patterns and a reconstruction of phylogenetic relationships within the genus. The checklist comprises 1,209 Allium taxa (1,140 species) belonging to 88 sections and 16 subgenera. Over 60% of 723 Allium species are strict endemics occurring in a single country. Phylogenetic reconstruction based on ITS sequences, including 460 species representing 80 sections and all 16 subgenera, strongly supports the existence of three major evolutionary lineages within Allium . In addition, analysis of global occurrence data from the Global Biodiversity Information Facility (GBIF) reveals that more than 85% of the total cleaned records were contributed by citizen scientists. We further examined global diversity patterns of Allium at the level of botanical countries. Our results show that: (i) native Allium species occur in 182 botanical countries; (ii) species richness, phylogenetic diversity, weighted endemism and phylogenetic endemism are strongly and positively correlated; and (iii) centers of neo-endemism, paleo-endemism and super-endemism are concentrated in North America and Mexico, southeastern Europe and western to eastern Asia and south-central China, respectively. These findings highlight the remarkable diversity of Allium and underscore the urgent need for further taxonomic, biogeographic and conservation-oriented research on this globally important genus.