The first report of Haplomitriumgibbsiae (Steph.) R.M. Schust. (Haplomitriaceae) from Guangxi, China.

Abstract

Background: The liverwort genus Haplomitrium, first described by Nees in 1833, is the basal sister group to all other liverworts. It exhibits distinctive traits, including upright shoots, radial leaf arrangement, abundant mucilage and the absence of rhizoids, reflecting its non-vascular nature. Predominantly found in the Southern Hemisphere, specifically Australasia, the genus comprises seven species and two infraspecific taxon globally, with China recording three species - H.blumei, H.mnioides and H.hookeri. These features and its distribution underscore its significance in studying early terrestrial flora.

New information: The liverwort species Haplomitriumgibbsiae (Steph.) R.M. Schust., previously considered endemic to Gondwanan regions, has been documented in East Asia for the first time during a floristic survey in the Jiuwanshan National Nature Reserve, Guangxi Zhuang Autonomous Region, China. This discovery expands the known range of the species and, when combined with prior hypotheses, suggests a potential dispersal pathway: following the fragmentation of Gondwana, H.gibbsiae may have spread to India and South America and subsequently from India to East Asia via the Himalayas, resulting in its present-day global distribution. Additionally, based on extensive literature review, the present study discusses the species' retention of primitive traits and considers its potential as a candidate for future research, aimed at deepening our understanding of early land plant evolution.