| The Oxytropis DC is considered to represent about 310 species in the world,133 of which are mainly distributed in the Qinghai-Tibet Plateau,southwestern Hengduan Mountains and northern area of China.This genus of plants is characterized by the beak vascular bundles reaching the apex of the corolla keel beak.The classification of Oxytropis DC species has been controversial for a long time.The classification of species is mostly based on specimens,and there are few classification studies based on the concept of "population".Micromorphological features have important significance in the classification of Fabaceae,but their taxonomic significance in Oxytropis DC lacks systematic research.Gansu is an important distribution area of Oxytropis DC,but so far,there is a lack of taxonomy research on Oxytropis DC.Therefore,this article conducted a taxonomic study on Oxytropis DC in Gansu Province by extensively reviewing the collected specimens and field population observations,combined with the literature verification and the micromorphology research of leaf epidermal and seeds,and discussed the classification of micromorphological characteristics in Oxytropis DC.The results are summarized as follows:1.The leaf epidermal cell morphology and taxonomic significance of 18 species and 2 varieties of Oxytropis DC were studied.It was found that there are two main types of leaf epidermal cell,i.e.polygonal and irregular;and the pattern of anticlinal walls has four types,that is straight-blow,sinuolate,undulate and sinuate.Types of stomata are irregular.The shape of epidermal cells and the pattern of anticlinal wall are stable in species,which can be used for species identification by combining with macroscopic morphological data.Stomatal characteristics are consistent in genera and can be used to study the systematic relationship between genera.Leaf epidermal micromorphological features are of great significance for exploring the classification and evolutionary relationships between Sections.2.The seed shape and seed coat ornamentation of 18 species and 2 varieties of Oxytropis DC.were significantly different in Sections and species.The seed shape within the species seems to be constant,which can be combined with macromorphological data for species identification and classification.The seed coat ornamentation has different conservativeness in different Sections.It is more conservative in the Sect.Mesogaea and can be used for species identification,while there are even variations within species in the Sect.Baicalia.The differences in conservation between Sections can also reflect the evolutionary relationship in Oxytropis DC.3.O.ningxiaensis C.W.Chang was treated as the variety of the O.giraldii Ulbrich,and a new combination was published: O.giraldii Ulbrich var.ningxiaensis(C.W.Chang.)X.Zhao et K.Sun comb.nov..4.Through field investigation and population variation analysis,it was found that there is a significant difference between the population of Xinglong Mountain in Gansu and Oxytropis ochrantha Turcz.,which was treated as a new variant: Oxytropis ochrantha Turcz.var.longisepala X.Zhao et K.Sun var.nov..5.The distribution of Oxytropis densiflora P.C.Li,Oxytropis trichophora Franchet and Oxytropis oxyphylla(Pallas)Candolle in Gansu province were excluded by specimen examination and literature review.6.Oxytropis muricata(Pallas)Candolle and Oxytropis zekuensis Y.H.Wu.were recognized as newly recorded species in Gansu province.7.Thirty-six species and three varieties of the Oxytropis DC.are recognized from Gansu,and their distribution in Gansu was clarified through specimen verification and field investigation. |
PDF Full Text Request