Molecular Phylogenics Of The Lycophytes Family Lycopodiaceae(Lycopodiales)

Lycopodiaceae are a family containing about 388 species distributed in all continents and the highest diversity is found in tropical regions.Previous studies on the cytology,morphology,anatomy,and molecular systematics have made substantial progress in understanding the diversity and evolution of the family,but major issues remain:(1)The family is morphologically simple and thus taxonomically difficult;(2)Because the samples and makers are less,the relationships amoung the genera have not been well established and the monophyly of the genera recognized has mostly not well been tested.Therefore,A molecular phylogenetics of Lycopodiaceae based on better samples and makers is desperately needed.In this study,the methods of maximum likelihood and maximum parsimony were used based on five plastid markers(rbcL,atpA,trnL-F,psbA-trnH,rps4-trnS)of 323 accessions representing about 130 species of Lycopodiaceae.The results show:(1)The tree is resolved into three major clades corresponding the three subfamilies: Huperzioideae,Lycopodioidieae and Lycopodielloideae;(2)Lycopodioidieae and Lycopodielloideae are more closely related than with Huperzioideae;(3)The three major clades are resolved into 17 clades,of which 16 represent 16 genera recognized in the PPG I classification,while Lycopodium serpentinum forms an independent clade.The 15 of the 16 clades are well supported(ML BS?96,MP JK?86)as monophyletic except for the Huperzia clade.The Huperzia clade received weak support(ML BS=50,MP JK=55).Preliminary studies show that Phylloglossum long branch attraction reduced value of Huperzia.After Phylloglossum is excluded,the monophyly of Huperzia is well supported(ML BS=80,MP JK=92).Although it is supported as sister for Huperzia and Phylloglosssum.But they have more differences at morphology and have distant genetic relation.Therefore this study accepts Huperzia and Phylloglosssum as independent genera.So our study supports the classfication of Lycopodiaceae by PPG I(2016)into three subfamilies and 16 genera,namely,Huperzioideae(Huperzia,Phlegmariurus,Phylloglossum),Lycopodielloideae(Lateristachys,Lycopodiella,Palhinhaea,Pseudolycopodiella),and Lycopodielloideae(Austrolycopodium,Dendrolycopodium,Diphasiastrum,Diphasium,Lycopodiastrum,Lycopodium,Pseudodiphasium,Pseudolycopodium,Spinulum).The Lycopodium serpentinum was published by Kunze in 1846.Our data did not resolve Lycopodium serpentinum as a member of either Lycopodiella or Pseudolycopodiella,but as sister to Palhinhaea.Since we only obtained chloroplast rbcL gene sequence from GenBank,this study do not deal with and the position of Lycopodium serpentinum requires more studies.