The Preliminary Study On The Flora Of Seed Plants In Yizu Mountain And Their Use

Yizu mountain from Yunnan Province are located in the southwest of the Central Yunnan Plateau,The research region has fallen between the Luzhijiang river and Yuanjiang river,between the Yishi river and the Yani river to the east and the Ede river to the south.The vegetation types of the Yizu mountain range from monsoon forests to mid-mountain wet evergreen broad-leaved forests,and it has diverse geographical environments and the sharp elevation drop.However,few surveys and studies on plants in this area have been done.Through field survey in different seasons,specimens collection and identification and literatures consultion,we have obtained a brief list of Yizu mountain,containing 993 species(including varieties and subspecies)which belong to 576 genera in 141 families.Among them,5 families,7 genera,9 species are gymnosperms;the other 136 families,569 genera,984 species are angiosperms.Based on wild seed plants including 139 families,561 genera and 972 species that this study identify it,we drew some conclusions through conducting statistical analysis of the wild seed palnts flora.(1)Analysis of family,genus and species,the modern flora of Yizu mountain mainly includes the tropical Asian elements,Chinese endemic elements and the Asian endemic elements.From the level of species,the proportion of tropical species was far more than the proportion of temperate species,and most tropical species are typical tropical Asian or pantropical species.On the other hand,the Chinese endemic species occupying a larger proportion are mostly tropical species that are located in the southwest and are distributed farther to the south.It can be seen that the wild seed flora in the Yizu mountain belongs to the subtropical flora.(2)Yizu mountain have obvious transitional features as a floristic node.For example,species as Duabanga grandiflora(Sonneratiaceae),Helicia nilagirica(Proteaceae),Homalium ceylanicum(Samydaceae),Falconeria insignis(Euphorbiaceae),Maytenus austroyunnanensis(Celastraceae),Markhamia stipulate(Bignoniaceae),Habenaria furcifera(Orchidaceae),Zeuxine goodyeroides(Orchidaceae),Pristimera cambodiana(Hippocrateaceae),Ventilago inaequilateralis(Rhamnaceae),Mitreola petiolata(Loganiaceae),which were used to be throught as limited in the south or southwestern of Yunnan had been found in this area.This research reveals the most northern boundary of the distribution of these taxa,and provides typical illustrations of the distribution of tropical components along deep valleys into high latitudes.(3)After the comparison with five adjacent regions(Xiaobaicaoling mountain,Xilong mountain,Jiaozi mountain,Wuliang mountain,Cangshan mountain)on the level of family,genus and specie,it could be concluded that the flora of Yizu mountain is most closely related to the flora of Xiaobaicaoling mountain.Both have similar floristic properties.(4)In the view of the endemism of 3 families and 37 genera and 170 species in East Asian,this area is a part of the East Asiatic Kingdom.The status of the flora of Yizu mountain in the East Asiatic Kingdom should be classified as Central Yunnan plateau subregion--Yunnan plateau region--Sino--Himalayan forest subkingdom.This paper also proposed some corresponding suggestions for distribution and control measures for exotic species,and protection of rare and endangered species.In addition,based on the investigation and arrangement of resource plants in the region,the paper make suggestions on their protection and utilization.