| Carex,with 1960~2000 species,is the worldwide largest genus of the family Cyperaceae.The section Molliculae,comprising approximately 20 species,mainly distributes in East Asia,and is difficult to distinguish each another,due to the various characters within this section.The relationship between sect.Molliculae and the sect.Confertiflorae is unresolved as well.Based on literature survey,specimen examination,field work,morphological and molecular evidences,a taxonomic revision is carried out and the main results are as follows.Morphology and micromorphology of the achenes of 17 species in sect.Molliculae and 10 species in sect.Confertiflorae were observed and measured.The shape of the achenes in sect.Molliculae is generally obovoid,rarely ovoid or ellipsoid,trigonous,with the size ranging from 1.47 to 2.45 mm.The epidermal cells are 5~7gonal,rarely circular or elliptical,with straight or microwave anticlinal walls,flat silica platform,solitary central silica body but non satellite silica bodies.The micromorphological characters of the achenes are stable in different populations of same species,whereas obvious differences among allies.The sect.Confertiflorae differs from sect.Molliculae by having several central silica bodies or satellite silica bodies in some species.The feature of the epidermal cells and anticlinal walls of Carex purpureotincta are the same as those of C.retrofracta,which reveals it belonging to sect.Confertiflorae.The epidermal micromorphology of C.phaenocarpa is different from the Carex japonica complex,which provides more evidence for its systematic placement.Morphology and micromorphology of the perigynia of 17 species in sect.Molliculae and 11 species in sect.Confertiflorae were observed and measured.The shape of the perigynia in sect.Molliculae is generally ovoid,rarely ellipsoid or obovoid,inflated-trigonous,glabrous,distinctly veined or not,with the size ranging from 2.48 to 4.86 mm long,apex contracted into a short,medium long or long beak,orifice 2-lobed teeth.The color of perigynia is yellowish green or stramineous,with the exception of Carex purpureotincta(brownish green)and C.phaenocarpa(yellowish brown).The micromorphological characters of the perigynia are frequently stable in different populations within same species,but obvious differences among allies.The perigynia morphology of C.purpureotincta is closest to C.retrofracta,which is placed into sect.Confertiflorae,and those of C.phaenocarpa differs from all members in sect.Molliculae.Furthermore,sect.Molliculae differs from sect.Confertiflorae by the color,indumentum and orifice of perigynia.Based upon the analysis of the combined sequences,ETS,ITS,trnL-F and matK,the phylogenetic relationship of 11 species in sect.Molliculae,14 species of sect.Confertiflorae,20 species and 1 variety of other sections was conducted.Both sect.Molliculae(except C.alliformis)and sect.Confertiflorae were all monophyletic,which was well-supporting the current status of these dependent sections.Three major clades were detected within Molliculae clade,viz.C.planiculmis clade,C.mollicula+ C.submollicula clade,which showed sister group,and C.japonica complex clade,the internal taxa can not be distinguished.C.alliformis was monophyletic that supported the established sect.Alliformes.It is clear that sect.Ischnostachyae and sect.Dispalatae should be incorporated into sect.Confertiflorae,and C.jaluensis and C.glauciformis were not the members in sect.Confertiflorae.PCA analysis and cluster analysis were performed on 24 morphological characters of 121 individuals,which were identified as 9 species in Carex japonica complex.The beak of perigynia,length of peduncles of terminal spike and length of the lowermost spike were the main distinguishable characters.C.japonica,C.huashanica,C.planiculmis and C.remotistachya could be easily distinguished from each another,whereas C.radicina and C.aphanolepis cannot,as well as C.alopecuroides and C.subtransversa.C.radicina and C.subtransversa were respectively reduced to the synonyms of C.aphanolepis and C.alopecuroides,and C.doniana was recognized as a variety of C.alopecuroides,which herein used the name C.alopecuroides var.chlorostachys.Based on all the above-mentioned evidences,the circumscription of sect.Molliculae was proposed and the taxonomic revision was conducted.11 species and 1variety were recognized,and 4 new synonyms were merged.A key to all recognitiontaxa was given,and the systematic placements of C.phaenocarpa,C.purpureotincta,C.xiangxiensis,C.alliformis and C.agglomerata var.rhizomata were discussed. |
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