| Arundinelleae(Poaceae,Panicoideae)comprises two genera(Arundinella Raddi and Ganotia Brongn)and ca.90 species.China accommodates both genera and ca.30 species of Arundinelleae,and southwest China is considered as one of the distribution centers of the tribe.The systematic position of Arundinelleae within subfamily Panicoideae has been controversial.Phylogenetic relationships within Arundinella and Ganotia are not resolved and both genera are taxonomically problematic.In this study,we adopted the multidisciplinary approach to further resolve the phylogenetic relationships within Arundinelleae and carried out a taxonomic revision of Arundinella and Garnotia from China.Our main results are as follows:1.A total of 130 DNA materials,118 collections and 260 duplicates of Arundinelleae were collected from our filed investigation.More than 6000 specimens of Arundinelleae from 40 herbaria all over the world were checked,including 252 type specimens.Protologues of all published names were also collated.2.The leaf anatomical structure of 34 individuals(28 species and two varieties)of Arundinelleae were examined.Two and three types of structure can be recognized in Arundinella and Garnotia,respectively.The leaf structure of Arundinelleae was shown to be of taxonomic significance.3.Micromorphological study on lemmas of 34 species and three varieties,pollen grains of 32 species and one variety,and seeds of 12 species and two varieties of Arundinelleae revealed that the curve of long cells in the lemmas and the distribution of prickle-hairs are of important taxonomic value,while the morphology of pollen and seeds is of limited value due to its low variation within the two genera.4.The whole plastomes of 51 individuals representing 40 species and three varieties of Arundinelleae were assembled and analyzed.Results showed that the plastomes of Arundinelleae are highly conserved in structure,gene order,and content.All 51 plastomes are consist of the LSC and SSC regions and a pair of IR regions.The size of the plastomes is ca.140,000 bp,and all plastomes encode 110 unique genes,including 76 protein-coding genes,30 tRNA genes,and four r RNA genes.All species have deletions of the accD,ycf1,ycf2 genes,and losses of the introgenic sequences of the clpP and rpoC1 genes.5.Phylogenomic study based on the plastome sequences of 144 individuals of 130 species and three varieties representing 11 tribes and 91 genera of Panicoideae revealed that both Arundinella and Garnotia are monophyletic and the two clades are recovered in a polytomy with tribe Andropogoneae,indicating that Arundinelleae might not be monophyletic.Combining with the morphological evidence,Garnotia is suggested to be placed in the monotypic Garnotieae.Phylogenetic relationships within Arundinella and Garnotia are well resolved and the previous infrageneric classifications of both genera are not supported.Four strongly supported clades can be recognized with Arundinella.6.Taxonomic revision of Arundinella and Garnotia from China was carried out based on the results from above analyses.In Arundinella,a new species is described and published,three new combinations are proposed,one species and one variant are resurrected.In Garnotia,a new species is described and one species is newly recorded from China.A total of two uncertain species,25 species and three varieties of Arundinella and seven species and one variety of Garnotia are recognized from China,including their species check key,and specimen citations are provided.In addition,the description and distribution of some species of the two genera are complemented.The lectotypes of several names are also designated. |
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