The Systematic And Taxonomie Studies Of Carex Sect. Mitratae (S.L.) Form China

Carex L.. the largest genus in the family Cyperaceae. which were divided into three subgenus, named Subgen. Indocarex,Subgen. Carex,Subgen. Vignea, contains about2000species around world and500species in China. In1753, Carex is set up by the famous botanist Linnaeus, a lot of researching of Carex had came forth after it, Kukenthal had done the creative work of Carex, aferword, new species of Carex had been found endlessly, and the researching means include morphological means, cytological means, molecular means and so on. The Sect. Mitratae(s.l.) is divided into Sect. Cryptostachyae,Sect. Lageniformes,Sect. Mitralae(s.s.) of Subgen.Carex. After summarizing and analyzing the researching status of Sect. Mitratae (s.l.), this study has some problems as follows:(1).Number of Carex species is large. Carex is widely distributing. The shape of plant of Sect. Mitratae (s.l.) is similar, some species have mutation.(2).The researching history of Sect. Mitratae (s.l.) is long, the taxonomic disposing of Sect. Mitratae (s.l.) has divarication.(3).The researching means of Carex in China is limited, not in-depth. Refer to these problems, the micromorphological characters of utricle,nutlet,epidermis,leaf structure with molecular means are choosed to do a systematic and taxonomic studies of Carex Sect. Mitratae(s.l.). Our result includes the follow aspects:1. The micromorphological characters of utricle and its systematic and taxonomic significanceThis study choose31Species and2varieties belong to Sect. Mitratae(s.l.), the shape and micromorphological characters of utricle were observed under scaning electronic microscope (SEM), the characters include Shape,Length,Width,L/W ratio,Type of beak,Surface concave,Surface main,Surface hair and so on. Based on the micromorphological characters, the Carex sect. Mitratae(s.l.) can be divided into three types:The type I set C. foraminate as model, include2species of C. foraminate and C. foraminatiformis, their utricle are small, length ranging from1.86to2.55mm, L/W Ratio ranging from1.52to2.25, beak orifice full eage, puberulent; The type Ⅱ set C. cryptostachys as model, include9species of C. cryptostachys, C breviscapa, C. truncatigluma and so on, most long ovate, length ranging from2.89to5.3mm, L/W ratio ranging from3.01to4.35, surface has concave, puberulent; The type III set C. mitrata as model, include22species of C. ascocerra,C. densipilosa, C. tenuispicula and so on. the shape of utricle is ovate, length ranging from2.28to3.44mm. L/W ratio ranging from1.52to2.99, the characters of beak orifice is various. The micromorphological characters of utricle is similar between the close species, can't divide Sect. Mitratae(s.l.) into Sect. Cryptostachyae,Sect. Lageniformes,Sect. Mitratae.2. The micromorphological characters of nutlet and its systematic and taxonomic significanceThis study choose31Species and2varieties belong to Sect. Mitratae(s.l.). the shape and micromorphological characters of nutlet were observed under scaning electronic microscope (SEM), the characters include Shape,Length,Width,L/W ratio,Arris concave,Arrisside concave,Cap structure,Beak structure,Stipitate, Silica cone. Surface Cell shape and its Anticlinal wall and so on. Based on the micromorphological characters, the Carex sect. Mitratae(s.l.) can be divided into three types:The type I set C. cryptostachys as model, include4species of C. ayptostachys,C. foraminate,C. dapanshanica and so on, this nutlet has beak structure, the cell of surface have several Silica cones; The type II set C. truncatigluma as model, include8species of C. truncatigluma, C. breviscapa, C. tenuispicula and so on, this type of nutlet has beak structure or cap structure, the shape of surface cell is anomalous, the anticlinal wall is undulated, has no silica cone; The type III set C. mitrata as model, include21species of C. ascocetra, C. densipilosa, C.mitrata and so on, the nutlet has cap structure, have one silica cone. The micromorphological characters of nutlet is similar between the close species, different between sections.3. The micromorphological characters of epidermis and its systematic and taxonomic significanceThis study choose31species,2varieties and1subspecies belong to Sect. Mitratae(s.l.), epidermis of leaf were observed under microscope, the characters include Cell shape size. Anticlinal wall,Attachment,Silica cone of upper epidermis, and Stomato index,Stomato size,Subsidiary cell shape,Cell shape size,Anticlinal wall,Attachment,Silica cone of lower epidermis. The micromorphological characters of epidermis don't have obvious difference between the three sections, and can't divide the Sect. Mitratae(s.l.) into Sect. Cryptostachyae,Sect. Lageniformes,Sect. Mitratae. but it is different between species, can use as evidence for distinguishing species.4. The micromorphological characters of leaf structure and its systematic and taxonomic significanceThis study choose31Species.2varieties and1subspecies belong to Sect. Mitratae(s.l.), leaf inside structure and micromorphological characters of main vein and side vein were observed under microscope, the characters include Leaf inner structure,Vascular bundle pairs,Shape of main vein,Height of main vein,Bulliform cell height,Vascular bundle shape,Width of main vein vascular bundle,Height of side vein,Vascular bundle shape,Width of side vein vascular bundle,Upper eperdimis height,Lower eperdimis height. The main difference of leaf structure between sections is the shape of main vein, the characters is obviously different between species include micromorphological characters and quantitative characters, can use as evidence for distinguishing species.5. Molecular researchThis study choose26Species and1varieties belong to Sect. Mitratae(s.l.) and Sect.Rhomboidales, use MP method, do a molecular phylogenetic research of Sect. Mitratae(s.l.) by nrDNA ITS squenece, cpDNA TrnL-F squenece. The result shows the Sect. Mitratae(s.l.) can't be divided into Sect. Cryptostachyae,Sect. Lageniformes,Sect. Mitratae.Basing on micromorphological characters and molecular evidence, Sect. Cryptostachyae,Sect. Lageniformes,Sect. Mitratae should be combined into one section This section contains40species and several varieties, subspecies, included2new species Car ex songyuniana X. F. Jin&Y. Zheng ined,Car ex wannanensis X. F. Jin&Y. Zheng ined., a new variety Carex chungii var. anhuiensis (S.W.SU et S.M.Xu) X. F. Jin&Y. Zheng, merged C. truncatigluma subsp. huayangensis and C. kobresiformis. Meanwhile. The taxonomic disposing of Carex chungii complex and Carex pisformis complex and the taxonomic disposing of variety and subspecies of Sect. Mitratae(s.l.) are appropriate. Carex chinesis is merged into Sect. Mitratae.