The discovery of taxol（2）possessing clinical activities against ovarian and breast cancer has stimu－lated a wide interest in the various Taxus species.Current interest in Taxus plants focuses on needles and barks of the plant in order to obtain taxol（2）and 10—deacetylbaccatin III．Recently,we got an opportunity to investigate the constituents of hte root of Taxus yunnanensis.From the ethereal extract of the root of ti－tled plant，We solated a new compound,named taxuyunnanine(1).

The determination of negative and positive fast atom bombardment mass spectrometry (FAB-MS) and field desorption mass spectrometry (FD-MS) were carred out on 25 iridoidal glycosides.The result showed that negative FAB-MS is more useful for the determination of mo-lecular weight and the structural elucidation of iridoidal glycosides than positive FAB-MS and FD-MS.

A new minor saponin, named notoginsenoside R7, was isolated from the roots of Panax notoginseng (Burk.) F. H. Chen. Its structure was established to be panaxadiol-3-0-β-D-glucopyranoside by means of chemical and spectral methods.In addition,a known polyacetylene compound, panaxytriol was isolated.

From the roots of Rubia yunnanensis,which is an antitumor drug used in Yunnan,an antitumor glycocyclohexapeptide(RY-l)was obtained previously[1]．Further study resulted in the isolation of a new antitumor glycocyclohexapeptide, RY—2．Its structure was elucidated on the basis of spectral and chemical methods.

A new antitumor glycocyclohexapeptide, RY- I , was isolated from Rubia yunnanensis together with its aglycone, RA-V ,which is an antitumor compound. The structure of RY-1 was elucidated by means of chemical and spectral methods and its biological activity was studied.

Two new diterpenoid quinones (dimer), xanthanthusin B (la) and xanthanthusin C (2a) and, taraxerol and oleanolic acid, were isolated from Coleus xanthanthus C. Y. Wu et Y. C. Huang by column chromatography on silica geL The structure of xanthanthusin B (la) and xanthanthusin C (2a) were elucidated respectively as (13S, 15S)-2a, 12a-diacetoxy-13-spiro-cyclopropyl-grandidon A (la) and 7-epi-xanthanthusin B (2a) by spectroscopic methods.

The chromosome at mitoticmetaphase were counted to be 2n=108. Of the 2n-108 somatic chromosomes, thirty two chromosomes are metacentric, twenty four chromosomes are submetacentric, twenty chromosome are acrocentric, and the remaining thirty two chromosomes are telocentric. The karyotype formala ofAdoxa orientalis Nepomn. is reported as follows for the frist time: 2n = 108 = 32m+24sm+20st+32t The chromosomes at rest stage and mitotic-prophase show the karyomorphological charac-ter to be the densely diffuse type and the continuous type.

Amentotaxus argotaenia (Hance) Pilger is valuable and imminent danger plant and be-longs tio the prior protective plant of third class in our county. It is dioecious. Through the chromosomal analysis at the cell of root tip, it is shown as below: the chromosome number in both the female and male plants is found to be 2n = 40. Among them both third to twentieth paris of chromosome are metacentric chromosomes, the third to twentieth paris of chromosome are telochromosomes. The karyootypic formula is 2n=40=4m+36T. Besides there is a little differ-ence of the second pair of chromosome in both the female plant and male plant. The relative length and arm ratio of the other pairs of chromosome all are more approximate. It may not be differentiae in the sex chromosomes.

In the present paper, the chromosome of 12 species in 11 genera of 7 famillies from the western Qinghai-Xizang Plateau were inverstigated in order to accumulate cytological data of this very species flora. Most of them are the dominant species to establish the plant communities of this region. Their karyotype formulas, and karyotype asymmtry following Stebbins's classification, are shown as follows: Chesneya nubigena (D.Don)Ali, 2n=16= 10m+ 6sm, 2Bi Caragana versicolor Benth., 2n=18= 14m+4sm, 2Bi Caragana gerardiana, 2n=18= 14m+4sm,2B;Dracocephalum heterophyllum Benth., 2n=24) Physochlaina praeslta,Kasing & A.M.Lu 2n=42=34m+8sm, 2Ai Lloydia serotina(L.) Reich.,2n=24=6m+ 10sm+8st, 3Bi Allium sikkimense Baker, 2n = 24 = 48 = 38m+6sm+4st,2A; Artemisia minor Jacq. ex DC., 2n=18=16m+2sm, 2A; Crepis flexuosa (Ledeb.)C.B.Clarke, 2n= 14=12m+2sm, 2Ai Microula tibetica Benth., 2n=24; Christolea crassifolia Camb., 2n=14=6m+6sm+2st.

Pollen grains of 32 species in the genus Adenophora from China were examined under the light microscope (LM)and scanning electron microscope (SEM). The results are as follows: (l)Nearly all species of the genus Adenophora possess similar type of spiny porotic pollen grains. Species, sub-species and varieties, however can be indetified by their different exine ornamentation, breadth of lirae, thickness of exine, density of spinule and condition of trema. (2) The evolution trends of the pollen grain in genus Adenophora are: from striate-reticulate, narrow lirae, roundish scrobiculus and dense spinules to striate, brain-gyrus, broad lirae, irregular scrobiculus and sparse spinules in the exine ornamentation. (3) According to this pollen study, conformed with the plant morphology and chromosome studies, the evolutionary tendency of the sections on the genus Adenophora is suggested as: Sect. Basiphyllus P. F. Tu et G. J. Xu→Sect. Ovatifolius P. F. Tu et G. J. Xu→ Sect.

Species affins C.delavayi Franch.et C.circaeoidi Hook.f.et Thoms.,sed foliis totis 3-foliolatis, foliolis ovato-rotundatis,supra raro pilis simplicibus obtectis,marginibus ciliatis,caule inferne,dense pilissimplicibus et furcatis intermixtis obtectis differt．

In this paper, a new species--Yinshania exiensis Y. H. Zhang is described. The charac-ters of the new species are similar to those of Y. chayuensis (Ser. Yinshanis) and Y. furcatopilosa (Ser. Henryanae). It is distributed in western Hubei. There are two sections and two series under the genus Yinshania. After the investigating of evolutional direction of the principal characters of Yinshania, it is considered that the Sect. Yinshania is an original group, and the Sect. Microcarpae is an advanced group. Western Sichuan and its near area is the center of distribution or the center of differentiation of Yinshania in morden times . This genus may be originated and differentiated from this area.

Corydalis Sect. Mucronatae Fedde ex C. Y. Wu et Z. Y. Su is an endemic section from west China, which comprises 6 species and 2 varieties, belonging to two series. It distributes in Sichuan, Yunnan and Guizhou provinces and reachs its greatest morphological diversity and concentration of species in W. Sichuan region. A brief diagnosis of the section is provided and four new species, two new varieties are described, viz. C. longkiensis, C. kailiensis, C. pinnata and C. longicalcarata in company with its var. non-saccata and var. multipinnata.

Affine A.brevicalarato Diles et A.scaposo Franch.,ab illo floribus minoribus,petalorum calcaribus multo longioribus conspicue circinatis,ab hoc pedicellis multo brevioribus,floribus minoribus differt.

The recorded number of the seed plants (besides planting)found in Lujiangba dry-hot valley which is below 1300 m amount to 361 species belonging to 259 genera of 81 families. Among them, Enteropogon is found in Yunnan for the first time. The flora, which has 51.5 tropical and subtropical families and 77.6 tropical genera, is obviously a tropical one, and it has close connection with the flora of pantropic, old world tropics, tropical Asia and tropical America.It means that the origin and connection with other tropical flora is quite ancient, re-flecting the relict background of Gondwana flora. The distribution of ?4 Gramineae plant has some links with climate, in this paper the writer points out that the number of this kind of plants can be used as one of the index to reflect the environmental dryness and hotness.

More than 20 species of the genus Caragana distributed mainly from Qinling mountain and northward and their 59 morphological characters were analyzed. Both phonogram and cladogram revealed that the taxa with pinnate or palmate leaves were grouped into clusters of their own. The cladogram showed that C. arborescens and its related taxa, C. stipitata ect. were primi-tive. Along the distributed region of C. arborescens, the genus radiated adaptively westward and southwestward into ecological series resulted from factors of temperature and precipitation, that is, I. forest species→forest→steppe species→steppe species→ desert species; forest species→ alpine montane species, II. humid zone→semihumid zone→semidrought zone→drought zone.

The origin systematics, fossil history and modern distribution of Chloranthaceae are discussed based on leaf architecture, wood anatomy, morphology and floral anatomy, palynology, fossil records and modem distribution pattern. Sarcandra and Chloranthus, both with bisexual and entomophilous flowers, have the closest phylogenetic relationship. Ascarina is most closely related to Hedyosmwn both being unisexual and anemophilous. Sarcandra would be the most primitive genus in extant four genera of Chloranthaceae, on the contrast, Hedyosmwn is the most advanced one. All proofs indicate that Chloranthaceae originate from the vesselless xylem and bisexual and entomophilous flower ancestor from which two groups derived. One is Sarcandra and Chloranthus and another Ascarina and Hedyosmum.Ttie earliest fossil record of Chloranthaceae is from the Barremian of the Lower Cretaceous. Four extant genera of Chloranthaceae had occurred in the Aptin.