Thistle be a mess:Untangling the taxonomy of Cirsium(Cardueae:Compositae)in North America  

作　　者：Jennifer R.Ackerfield David J.Keil Wendy C.Hodgson Mark P.Simmons Shannon D.Fehlberg Vicki A.Funk 

机构地区：[1]Department of Biology,Colorado State University,Fort Collins,CO 80523-1878,USA [2]Denver Botanic Gardens,1007 York St.Denver,CO 80206,USA [3]Department of Botany,National Museum of Natural History,Smithsonian Institution,10th and Constitution Ave.Washington,DC 20560-0166,USA [4]Department of Biological Sciences,California Polytechnic State University,San Luis Obispo,CA 93407,USA [5]Desert Botanical Garden,Research,Conservation,and Collections,1201 North Galvin Parkway Phoenix,AZ 85008,USA

出　　处：《Journal of Systematics and Evolution》2020年第6期881-912,共32页植物分类学报（英文版）

基　　金：This work was supported in part by funding to Jennifer Ackerfield from the American Society of Plant Taxonomists Graduate Student Research Award,Colorado Mountain Club Foundation Research Grant,Colorado Native Plant Society Marr Grant and Steinkamp Fund,Colorado State University H.D.Harrington Fund,Colorado State University Stavros Family Fund,Smithsonian Institution Predoctoral Fellowship,Society of Herbarium Curators Student Research Award,and Utah Native Plant Society Research Grant.

摘　　要：Cirsium(i.e.,“thistles”)are one of the most taxonomically challenging groups of Compositae in North America.This study represents the first attempt to infer a broadly sampled phylogeny of Cirsium in North America.The two main objectives are to:(i)test whether currently hypothesized species variety complexes(C.arizonicum,C.clavatum,C.eatonii,and C.scariosum)constitute monophyletic lineages,and(ii)recircumscribe any taxa that are identified as problematic.Phylogeny reconstructions based on DNA sequence data from two nuclear ribosomal regions and four plastid markers were used to infer evolutionary lineages and test species’delimitations.Eight species varietal complexes were resolved as polyphyletic.We recircumscribed these complexes and in doing so found evidence to support the recognition of six new taxa.We hypothesize that the extensive taxonomic difficulty within Cirsium is the result of several factors:(i)previously undescribed taxa,(ii)inadequate representation of taxa from herbarium specimens,(iii)phenotypic convergence,(iv)hybridization,and(v)incipient speciation.While we can provide evidence to support the recircumscription of some taxa,others remain unresolved.Therefore,we are working on a phylogenomic study of North American Cirsium to answer remaining taxonomic questions as well as provide a robust framework for biogeographic studies.

关 键 词：adaptive radiation Asteraceae CIRSIUM COMPOSITAE continental radiation convergence HYBRIDIZATION 

分 类 号：Q94[生物学—植物学]