Taxonomic Revision Of The Loranthaceae And Distribution Patterns Research Form Hainan Province

For a long time,the classification of family,genus and species of Loranthaceae plants has been debated.Loranthaceae plants affect the growth of crops to a certain extent,which further affects the interests of farmers.However,Loranthaceae plants are commonly used in drugs in ancient China.They have different hosts,and the medicinal components are significantly different.In order to clarify the species and host diversity of Loranthaceae plants in Hainan,and to learn about the parasitic habits of mulberry parasites,we reviewed literature and specimens,conducted field investigation and laboratory tests,revised the parasitic plants of Hainan Mulberry,and studied their parasitic habits.The main findings are as follows:(1)Through field investigation,specimen identification,and related literatures,we used the traditional Loranthaceae concept,and identified 7 genera,22 species,2 varietas and 1 species inquirenda.Among them,Viscum hainanense is endemic.We revised and produced a classification and retrieval table of various genera and species.We also described and revised the data,geographical distribution and source of specimens of each species.(2)We checked the voucher specimen,confirmed that Viscum Yunnanense is not produced in Hainan,but in Yunnan Mengla.So,Viscum Yunnanense is wrongly recorded to be a product of Hainan records.The correct record should be Hainan's unique species of Viscum Hainanense,which is produced in Hainan Changjiang Bawangling National Nature Reserve.It is found that there are some differences between the parasitic and the pattern specimens recorded in Hainan,but the number of specimens is tentative because of the shortage of specimen.(3)The species of Loranthaceae plants in Hainan Island are abundant,but the distribution is not optimistic.Most kinds of specimens have very few records,and 12 species have not been seen in this survey.The parasitic plants of mulberry in Hainan Island are unevenly distributed in horizontal and vertical directions.In the horizontal direction,cities and counties in the northwest and northeast of Hainan Island are significantly lower than the central mountainous areas.In the vertical direction,at an elevation of less than 600m,12 common species are distributed,and above the elevation of 1200m,only 6 species are distributed,and most of them are rare species.(4)Taxillus chinensis has the most variety of host species.Hainan mistletoe has shown a strong specificity.Fabaceae plants are most very susceptible to infection.Ficus plants are relatively susceptible to infection and parasitism.The Euphorbiaceae plants are infected by the most variety of mulberry parasitic plants;the rubber tree can be infected by 7 species of the Loranthaceae plants;sometimes,a same host plant is infected by multiple parasites.About 98%of the hosts are dicotyledons,and 75%are trees.(5)Loranthaceae plants and its genera are tropical distribution types.The host plants are at the level of the family and genus,and the highest proportion of their distribution types are pan-tropical distribution.There are 25 families and 108 genera,accounting for 49.03%and 28.13%respectively.At the level family and genus,tropical plants are significantly more than temperate plants.(6)In the Danzhou campus of Hainan University,the most hosts of Loranthaceae plants are located in residential areas,and the infection rate is only 9.2%.On the contrary,fewer hosts of Loranthaceae plants are located in the main road,but the infection rate is as high as 18.8%.The distribution patterns of the sheath of the flat branch mistletoe,the tumor fruit mistletoe and the main road are not clustered,and the parasitic regions of the remaining different species are clustered and more concentrated.(7)The chloroplast whole genome series of Scurrula notothixoide is 123810 bp.It is divided into 4 regions and 88 genes.The total A/T content of chloroplast is 62.7%.The maximum likelihood(ML)is used to establish a phylogenetic tree.Scurrula notothixoide and Loranthaceae are closely related.All members of santalales are gathered together,producing a high support(BS)value.