A New Species of Ehretia, Ehretia retroserrata in Nujiang County, Yunnan Province, China

On the investigation of the biodiverisities of plant resources of Nujiang River Valley in Nujiang Autonomous Prefacure, Yunnan Province, China, a new species of Ehretia has been described and illustrated as Ehretia retroserrata in the arid valley of Nujiang according to the new living state of erect shrub and the characteristics of serrate leave margin, retrose, apiculate, endocarp divided at maturity into 4 1-seeded pyrene and serrate leaves margins by comparison with other species of the genus Ehretia.


Introduction
There are 14 species in genus Ehretia in China.Most of them are arbors more than 10 meters high.There are 7 species in Yunnan Province and all of them are arbors.Among all the species of genus Ehretia in China, only E. changjiang and E. asperula are climbing shrubs in Hainan Province.On the identification research of Eheria, firstly, 2 groups have been classified according to the differences between "serrate leaves; endocarp divided at maturity into 2 2-seeded pyrenes" and "entire leaves margins, endocarp divided at maturity into 4 1-seeded pyrenes", so that E. acuminata, E. corylifolia and E. dicksonii have been classified as the 1 st group and the 2 nd group includes E. confinis, E. tsangi, E. dunniana and E. longiflora etc.Secondly, in the 1 st group, according to the differences of "glabrous leaves, antrorse, apiculate teeth; corolla lobes longer than tube; drupes 3 -4 mm in diam" and "abaxially pubescent leaves, spreading teeth, not apiculate; corolla lobes shorter than tube; drupes 6 -15 mm in diam", E. acuminata and E. corylifolia have been classified as 2 species.E. changjiang and E. asperula are only climbing shrubs found in Hainan Province, but their leaves are leathery and have entire margins and pubescent cymes [1]- [4].Another species of Japan, E. microphylla has the unique characteristic of long obovate leaves with white seta and white basal plate.

Materials & Methods
Specimens have been collected by Fan Du on June 2, 2014 on the 30˚ slope in the dry red soil with 40% limestone naked in Mangkuan, Dai and Yi National Xiang, Longyang District, Baoshan City, in the arid valley of Nujiang Prefecture, Yunnan Province, China, with the south altitude of 807 m, E25˚38'25.1''and N98˚52'25.1''.
By taxonomy and comparative anatomy methods, the following result shows.
1.According to the index of genus Ehretia, erect shrub is a new characteristic among all the species while E. changjiangensis and E. asperula are Climbing shrubs in Hainan Province and the other species are arbors, mostly higher than 10 m [2].
3. The most conspicuous characteristic of E. retroserrata is: "front serrate retrorse, apiculate", which is a compensation to the other species of "Leaves glabrous, teeth antrorse, apiculate; corolla lobes longer than tube; drupes 3 -4 mm in diam" and "Leaves pubescent abaxially, teeth spreading, not apiculate; corolla lobes shorter than tube; drupes 6 -15 mm in diam" [2].So it has been named.Here we would no doubt the miracles of nature and the sequences of God creating the world.

Conclusions
Ehretia S. S Yang & F. Du, sp.Nov (Figure 1) Ehetia retroserrata S. S Yang & F. Du, sp.nov is a new species of genus Ehretia found in the arid valley of Nujiang Valley, in a very narrow area near tillage land, and only several plants have been found in a limestone shrubs in an extremely dry ecological state.It has the characteristics of small leaves, small flowers and small drupes and indumentum developed like E. changjiang and E. asperula in Hainan Province.The arid ecology is similar to that of the two later species in Hainan Province, and they have the similar characteristics of shrubs instead of arbors.E. retroserrata has the new characteristic of erect shrub, serrate leaves margins, endocarp divided at maturity into 4 1-seeded pyrenes and glabrous leaves, teeth retrose (Figure 2 & Figure 3), apiculate corolla lobes shorter than tube, drupes 3 -4 mm in diam, puberulent calyx, pilose style, pubescent corrola lobes, leaves oli glands.
Finally, the biological protection should be emphasized and adopted in case of endangerment by the tillage.

Figure 2 .
Figure 2. The organs of flowers & leaves etc.