| The lichen genus Herpothallon is classified into Arthoniaceae,Arthoniales,Arthoniomycetes,Ascomycota,Fungi.Holotype: Herpothallon sanguineum.Herpothallon includes 50 species wordwide,of which 8 species have found in China.Herpothallon is pantropical,abundantly growing in the humid and shady places.The main distinguishing features are: thallus is crustose,mostly corticolous,rarely foliicolous,saxicolous or muscicolous,some species can grow on metal surfaces,felty to byssoid,usually forming rounded to irregular patches,almost white,pale yellowish,greenish-grey,green or with yellow,orange or red colouration;hypothallus and prothallus byssoid,white;pseudisidia or pseudisidioid structures are common;photobiont trentepohlioid;usually sterile;contain a diverse chemistry with psoromic,gyrophoric and confluentic acids as most frequently occurring substances.This research is to study the species diversity of Herpothallon in China.Based on morphological,anatomical and chemical analysis,280 specimens of Herpothallon were classified and described.Photos of each species were added in appendix,an updated key to the genus Herpothallon in China and a phylogenetic tree were presented.On the basis of taxonomic identification,we analyzed the species diversity of this group in China,discussed its substrate types and altitude distribution characteristics,identify the distribution of each species in China and around the world.The geographical distribution types of Herpothallon in China were divided according to the existing literature.Research results: In this study,30 mt SSU sequences were obtained,and 12 of them were selected to establish a phylogenetic tree.Through phylogenetic analysis and species definition analysis,the phylogenetic relationships among some Herpothallon species were clarified,providing scientific basis for establishing a more natural classification system.The species of Herpothallon in China are mainly growing on barks(100%),rarely on rocks(22.7%)and leaves(13.6%).Among the 22 Herpothallon species,17 species are only corticolous,accounting for about 72.7% of the total known species in China.The growth substrates of H.echinatum and H.fibrosa are diverse,can grow on barks,leaves and rocks,H.echinatum can also grow on metal surfaces,has the strongest adaptability to the environment.The vertical distribution of Herpothallon in China is wide,mainly in the altitude range of150 m–2500 m,which is consistent with the habitat preference of this group.Among these,H.echinatum has the widest vertical distribution range,and the altitude difference between the highest point and the lowest point is over 2500 m.The vertical distribution range of H.australasicum,H.polyisidiatum and H.subglobosum is second,with the lowest being about 200 m and the highest being about 2000 m.In this study,22 species of the Herpothallon were identified.Among them,6 new species were discovered and described: H.bicolor,H.fibrosa,H.glaucescens,H.lilacinum,H.tomentosum,H.subminutum;8 new records in China: H.australasicum,H.cinereum,H.granulosum,H.himalayanum,H.isidiatum,H.japonicum,H.minitum,H.queenslandicum;The remaining 8 species have been reported in China.In flora division,these 22 species of Herpothallon can be classified into 5 geographical distribution types: Pantropical(9.1%),Tropical Asia to Tropical Australia(9.1%),Topical Asia and Tropical America(9.1%),Tropical Asia,(22.7%)and Endemic to China(50.0%).Among these,the Endemic to China element possesses 11 species,and the second abundant element is Tropical Asia element which contains 5 species,which are the two main geographical elements,16 species in total,72.7% of the whole species.This study is the first to explore the distribution characteristics and geographical flora of Herpothallon.The results show that the species diversity of Herpothallon is relatively high in southern China,which is of great significance for identifying the species composition of Herpothallon in China,provides a theoretical basis for protecting and utilizing lichen resources. |
