Systematic Study On Phleum Etc.Five Genera Of The Subfamily Pooideae(Poaceae)Distributed In China

Phleum,Alopecrus,Beckmannia,Aniselytron and Anisachne belong to subfamily Pooideae of Poaceae.When these genera were established,their systematic positions were uncertain.Phleum and Alopecrus were placed within Agrostideae in Flora Illustralis Plantarum Primarum Sinicarum(Gramineae)and Flora Reipublicae Popularis Sinicae.In Families and Genera of Angiosperms in China,a Comprehensive Analysis those two genera were treated as members of Alopecurinae,Aveneae,whereas were treated as members of Pharalideae in Systematics of Spermatophyta.Tzvelev assigned these two genera to Phleeae.In Flora of China the two genera were placed in Aveneae.Beckmannia has been placed in Phlarideae,Paniceae,Chlorideae,Agrostideae,Poeae,Aveneae,among other tribes.Aniselytron has been treated as a part of Calamagrostis Adans.s.L.,and also been placed in Agrostideae,Aveneae and Poeae.Anisachne was treated as a separate genus in Flora Reipublicae Popularis Sinicae and The Families and Genera of Angiosperms in China,a Comprehensive Analysis,but others didn't adopt this idea and placed it in Calamagrostis,Aniselytron,Agrostis and Deyeuxia.Thus,further study and analysis is required to define the phylogenetics of the five genera.In this study,leaf epidermis,caryopsis morphology,silica body morphology,glume,lemma and palea epidermis,and molecular systematics were used to analyze the phylogenetic positions of the five genera.The results are as follows:Leaf epidermal micromorphology:29 characters were selected for cluster analysis,and the plants mainly divided into two clades.The Oryzeae,Bambuseae,Eragrostideae,Cynodonteae,Arundineae,Arundinelleae,Paniceae,Andropogoneae and Isachneae,which belong to the Oryzoideae,Bambusoideae,Eragrostoideae,Arundinoideae and Panicoideae subfamilies,form Clade A.Clade B includes Poeae,Aveneae,Stipeae,Triticeae,Bromeae and Diarrheneae,and belongs to a monophyletic Pooideae.The genera of Phleum,Alopecrus,Beckmannia,Aniselytron,Dactylis,Poa,Lolium,Milium,Festuca and Vulpi composed a group,and Anisachne,Deyeuxia,Polypogon,Koeleria,Anthoxanthum,Avena composed a group.The results of leaf epidermal micromorphology evidences showed that Phleum,Alopecrus,Beckmannia,Aniselytron are closely related to Poeae,the systematic positions of Phleum,Alopecrus should be replaced in Poeae,and Beckmannia also should be placed in Poeae.Aniselytron was suggested to be treated as a separate genus and placed in Poeae.Anisachne should be placed in Deyeuxia.Carpology:Based on the size,shape,colour,compressed mode,ventral view,stylopodium,villi,embryo ratio,hilum type and sculpturing pattern,we divided the plants into four types and three subtypes.Phleum,Alopecrus,Beckmannia,Aniselytron with suborbicular hilum and reticulate spermoderm pattern shared the same subtype with the genera of Poa and Puccinellia.The results indicated that the four genera are closely related to Poeae and was suggested to be placed in Poeae.Besides,the spermoderm patterns of Alopecrus and Beckmannia were rectangular reticulate,which indicated that Alopecurus and Beckmannia may have a closer relationship.The caryopsis of Anisachne with ventral concave,fluted,lanceolate to slit-like hilum and striate pattern belongs to type IV subtype ii.The Anisachne was classified in the same subtype with Deyeuxia,Hierochloe,Phalaris,Agrostis,Calamagrostis and Polypogon of Aveneae,showed that Anisachne had a close relationship with Aveneae.The results showed that caryopsis morphological characteristics of Anisachne and Deyeuxia were highly consistent.Therefore,caryopsis micromorphological evidences supported the idea of Chen that Anisachne should be placed in Deyeuxia.A key to identify the different genera is provided.Silica body morphology:Five types and four subtypes were distinguished based on the shape,arrangement,aspect ratio and containing granule of silica bodies.The exact systematic positions of Phleum,Alopecrus,Beckmannia and Aniselytron were not well determined only according to the silica bodies characteristics.The silica body of Anisachne is nodular and aspect ratio is about 3.2,vertical arrangement and containing 4-5 granules,which is similar to Deyeuxia with an aspect ratio of about 3-5 and 1-5 containing granules.Silica bodies characteristics supported Anisachne should be merged into Deyeuxia.Glume,lemma and palea epidermal micromorphology:Based on a comprehensive analysis of the first glume,second glume,lemma and palea micro morphological characteristics,the plants were divided into six types and three subtypes.Phleum,Alopecrus,Beckmannia and Aniselytron were classified in the same subtype with Poa,Puccinellia,Festuca,Lolium,Vulpia and Milium according to costal silica cells of the glumes were suborbicular or absent,subsidiary cells were parallelled to low dome shaped,prickles of lemmas were frequently occurred both in costal and intercostal zones.The characteristics of glume,lemma and palea epidermis showed that Phleum,Alopecrus,Beckmannia and Aniselytron were closely related to Poeae.The four genera should be placed in Poeae.Anisachne and Deyeuxia have similar characteristics in intercostal cork-cells,subsidiary cells of glumes and intercostal long-cells and costal silica cells of lemmas and paleas.The characteristics of glume,lemma and palea epidermis supported Anisachne merged into Deyeuxia.Molecular phylogeny:In the present study,nuclear ribosomal ITS and plastid trnL-F,psbA-trnH and rbcL sequences were used to reconstruct phylogenies of phleum etc.five genera and their related genera using Bayesian-and maximum likelihood-based analyses.The phylogenetic analyses revealed that Phleum,Alopecrus,Beckmannia,Aniselytron are closely related to Poeae,they should be placed in Poeae,and Anisachne should be placed in Deyeuxia.The overall topology and the values of the phylogram derived from the combined data tree were better than those of the individual data trees.The combined data can effectively increase phylogenetic informations,reduce noises,and improve the accuracy of the phylogenetic reconstruction.New-recorded species from Shandong:Hordeum jubatum Linnaeus and Neyraudia reynaudiana(Kunth)Keng ex Hitchcock,two newly naturalized species from Shandong were found.In conclusion,Phleum,Alopecrus,Beckmannia,Aniselytron were closely related to Poeae.The systematic position of Phleum,Alopecrus should be replaced in Poeae,and Beckmannia also should be placed in Poeae.Aniselytron should be treated as a separate genus and placed in Poeae.Anisachne should not be a separate genus,it should be a member of Deyeuxia.