Once Again on the Distribution of Syzygiella (Adelanthaceae, Marchantiophyta) in Indochina

Abstract

The distribution of known Syzygiella taxa in Indochina was reviewed. Currently, four species are known in Indochina: S. autumnalis, S. elongella, S. nipponica, and S. securifolia. This genus is reported for the first time in the flora of Cambodia, and S. securifolia is newly recorded for Vietnam. Herein, a description of oil bodies for S. securifolia is provided for the first time. A morphological description of the species and intravital photographs, as well as line-art illustrations, are provided along with the identification key to the Syzygiella taxa known in Indochina. A comparison of the climatic parameters of the collection sites for four known species showed that three of them occupy a relatively marginal position in the flora of Indochina as a whole and are known from colder biomes on the very northern edge of the peninsula. The locations of Syzygiella securifolia are scattered not only on the geographical map of Indochina but also on the bioclimatic scatterplot; these locations are likely an underestimation of the distribution of this taxon in Indochina, although it is generally rare worldwide. A comparison of lists of liverworts across the countries of Indochina will help identify groups of taxa for further targeted searches with the purpose of obtaining more comprehensive knowledge of the biodiversity of still poorly studied Indochina countries.