Table of Contents

10 March 1998, Volume 36 Issue 2
    Research Articles
  • WANG Xiao-Quan, LI Zhen-Yu
    J Syst Evol. 1998, 36(2): 97-105.
    A molecular phylogeny of the subfamily Cyrtandroideae represented by five genera of four tribes was constructed using sequence analysis of the internal transcribed spacers (ITS) and partial 5.8 S rRNA gene (3’end) of nuclear ribosomal DNA. Direct PCR sequencing method was used in the study. The sequences of ITS-1 in the five species range from 234 bp to 258 bp in size and those of ITS-2 from 218 bp to 246 bp. The ITS-1 (258 bp) and ITS-2 (218 bp) of Whytockia bijieensis differ greatly from those of the other species in size, sequence and G + C content, and therefore the tribe Klugieae represented by W. bijieensis may have diverged from the ancestor of the subfamily Cyrtandroideae at a very early time. In PAUP analysis, W. bijieensis was used as the functional outgroup, and only one most parsimonious Fitch tree was obtained through exhaustive search. The tree has 353 steps, with CI = 0. 932 and RI = 0. 529. In the tree, Chirita crassifolia is basal to a monophyletic group comprising Cyrtandra umbellifera, Briggisia longipes and Anna mollifolia, and the monophyletic group is strongly supported by the bootstrap value (97). The tribes Trichosporeae and Cyrtandreae represented respectively by Anna mollifolia and Cyrtandra urnbellifera both evolved from the tribe Didymorcarpeae, which can explain why many intermediate taxa exist among the three tribes. According to this, the present authors suggest that the tribe Trichosporeae and the tribe Cyrtandreae be merged with the tribeDidymocarpeae.
  • HONG De-Yuan, PAN Kai-Yu
    J Syst Evol. 1998, 36(2): 106-110.
    The genus Cyclocodon Griff. was reduced by C. B. Clarke in 1881 into a section of the genus Campanumoea. Our LM and SEM observations on pollen morphology show that the pollen of all the three species in the former is 3-colporate with the exine sparsely high-spinulose, whereas that of the two species in the latter is 5~8-colpate with the exine relatively densely short-spinulose. SEM observations on seed-coat indicate that the primary ornamentation of the seed-coat of the two species in Campanumoea (s. str. ) is characterized by regular and polygonal areoles which are much larger than the radial walls in diameter and by the bead-like secondary ornamentation on the radial walls, while that of the three species in Cyclocodon is characterized by irregular-shaped areoles which are nearly equal to the radial walls in diameter and by the rope-like secondary ornamentation on the radial walls. Thus, the pollen morphology is closely correlated with the seed-coat morphology. Taking the characteristics of pollen, seed-coat and gross morphology into consideration, the genus Cyclocodon is restored, separate from Campanumoea (s. str. ). One new combination, Cyclocodon celebicus (B1.)Hong, is made in the present paper. The genus Cyclocodon is con-sidered closely related to Platycodon rather than to Campanumoa.
  • LIU Lin-De, WANG Zhong-Li, TIAN Guo-Wei, SHEN Jia-Heng
    J Syst Evol. 1998, 36(2): 111-118.
    The development status of gynoecia in Eleutherococcus senticosus flowers is different from that in ordinary plants. Female gametophytes of E. senticosus have not become mature until the 6th day after anthesis. On the 6th day, 82.25% of embryo sacs in female plants, and 67.25% of those in hermaphroditic plants become mature, while the rest are sterile, immature or degenerated with no fertilized embryo sacs observed. At the same time, all embryo sacs degenerated and flowers withered in male plants. On the 7th day, a few embryo sacs in female and hermaphroditic plants start being fertilized. Accompanying the differentiation of embryo sacs, styles of female and hermaphroditic flowers start to expand and their nectaries become mature gradually. After the 4th or 6th day of anthesis, stigmatic papillae become conspicious and stigmata become white and open. In the meantime, the stigmata become receptive and the nectaries get active or reactive. By the 9th or 10th day, 40~65 % of embryo sacs in female plants and 25~41% of those in hermaphroditic plants have been fertilized. The whole process of fertilization in E. senticosus was observed. About 2 or 3 days after pollination, the two sperm nuclei start to fuse with the egg and the secondary nucleus. The fertilization of E. senticosus belongs to the premitotic type of syngamy. The essential process of the fusion of male and female nuclei during syngamy may be generalized as follows: (1) the contacting of male nucleus with the female one; (2) the fusion of nuclear membranes between the male and female nuclei; (3) the despiralization of male spireme and the appearance of male nucleolus inside the fertilized female nucleus; (4) the dispersion of male chromatin and the mergence with the female chromatin, which is the sign of completion of the fusion of the two nuclei. In addition, degeneration types of mature embryo sacs were observed. And typical polyspermy and a series of cases in which extra sperms enter the em-bryo sac are recorded.
  • LIU Wen-Zhe, HU Zheng-Hai
    J Syst Evol. 1998, 36(2): 119-127.
    Comparative observations were made on the morphology and anatomy of secretory cavities in leaves of 22 genera, 40 species and two varieties by the whole mounting, paraffin and thin section method. A mature cavity consists of one layer of epithelial cells surrounding a large intercellular space and one to five layers of peripheral sheath cells. The epithelial cells were flattened, thin-walled and integrated, which suggests that the cavities developed schizogenously. The sheath cells were also flattened. The cell walls of the outer layers had relative thickenings. The number of layers of the sheath cells varied with species. A few of species appeared to lack the sheath cells. The localization and structure of the cavities were correlated with taxa at generic and specific level. According to their structural features and arrangement in leaves, the secretory cavities can be grouped into four types as follows: the notch type (between the leaf-teeth), the mesophyll type which is subdivided into spongy parenchyma subtype and palisade parenchyma subtype, and the mixed type (with both notch and mesophyll cavities). Based on these observations evolutionary trends concerning the morphology and anatomy of cavities and affinity among subfamilies or genera are discussed. It issuggested that the mixed type of cavities developed from the notch and mesophyll types.
  • TIAN Guo-Wei, WANG Zhong-Li, LIU Lin-De, SHEN Jia-Heng
    J Syst Evol. 1998, 36(2): 128-133.
    Seeds of Eleutherococcus brachypus Harms were flat-kidney-shaped and their seed coats were only composed of one layer of cells. Embryos with abundant protein in their cells were just at the heart-shaped stage and were capped by sacs formed from degenerating endosperm cells when seeds shed from their maternal plants. A large amount of stored protein grains and lipids existed in endosperm cells but no polysaccharide grains were present either in endosperm cells or in embryo cells. Viable seeds were only 9.27% of the total. The plump seeds germinated in the cultivated field after 18~19 months and their germinating rate was 1.67%. Besides, the content of protein decreased gradually and a few polysaccharide grains were stored in embryo cells during the process. The afterripening process of seeds stratified at different temperatures ended after 6 months and the cytochemistry features of the seeds were that the content of protein decreased gradually and numerous polysaccharide grains had been stored in embryo cells at the late heart-shaped embryo stage and retained till the mature embryo stage. The structure, afterripening and cytochemistry of seeds were compared between Eleutherococcus brachypus and Eleutherococcus senticosus. The poor quality of the seeds, longer time of afterripening in a natural state and much lower germination rate of E. brachypus are considered to be important reasons for the endangerment of this species. Somemeasures are suggested for its conservation based on the above facts.
  • LUO Yi-Bo, PEI Yan-Long, PAN Kai-Yu, HONG De-Yuan
    J Syst Evol. 1998, 36(2): 134-144.
    Field observation on pollination in three populations of Paeonia suffruticosa subsp. spontanea in southern Shanxi Province showed that five species of bees in two families and four species of beetles were engaged in pollination. Examination on bodies of these in sects under SEM, and seed set produced by controlled insect-pollination indicated that the bees, especially the species in the genus Andrena were main pollinators and the beetles except those of small size were only fluctuating vectors. Flowers of this taxon are scented and nonectariferous. Flowers attracted bees and beetles mainly by pollen. A study on seed-set in the three populations revealed considerable variation within and among populations. The plants were no apomict and autogamy, but geitonogamy sometimes could produce mature seeds (x= 2.86 seeds per carpel). In the population with less flowers (less than 40 flowers), natural seed-set (x=3.88) was close to the seed-set produced by hand cross-pollination (x = 3.21), but in the population with more flowers(near 100 flowers) natural seed-set (x= 2.48) was lower than that by hand cross-pollination (x = 3.21). The seed-set was low for both natural and artificial cross-pollination with only about one forth of ovules developing into seeds.
  • LI Xiu-Lan, SONG Wen-Qin, AN Zhu-Ping, CHEN Rui-Yang
    J Syst Evol. 1998, 36(2): 145-149.
    Karyotypes of 12 species of Michelia in the Magnoliaceae were studied. Theirkaryotype formulas are: M. macclurei var. sublanea 2n=34m(2SAT)+4sm; M. alba 2n=34m+4sm; M. floribunda 2n=30m+8sm; M. champaca 2n=32m+6sm; M. shiluensis 2n=32m+6sm; M. platypetala 2n=32m+6sm(2SAT); M. figo 2n=32m+6sm; M. maudiae 2n=32m+6sm; M. longistamina 2n=32m+6sm; M. foveolata 2n=34m+4sm; M. skineriana 2n=30m+8sm; M. wilsonii 2n=30m+8sm(2SAT). All the species are of the symmetrical karyotype. The karyotypes all belong to 2A type except that of M. floribunda which is of 1A type. Due to the karyotype similarity among species, the karyotype data in Michelia may be hardly useful for infrageneric taxonomy.
  • WANG Wen-Tsai
    J Syst Evol. 1998, 36(2): 150-172.
    (1) In the overwhelming majority of genera of the family Ranunculaceae, includ ing its primitive genera, Caltha, Calathodes, and Trollius and the primitive genus of trib. Anemoneae, Anemone, the sepals are spreading and the stamens are glabrous. So, the as cending or upright sepals and hairy stamens of the sections Meclatis, Tubulosa, Viorna, and Atragene of the genus Clematis are secondary, and are accordingly considered as advanced characters, and those sections and the genus Archiclematis, closely related to Sect. Viorna Subsect. Connatae, more or less advanced groups. (2) In the sections Cheiropsis, Fruticella, and Viticella, which have glabrous stamens,some species have spreading sepals, and the others have ascending or upright sepals. In Sect. Clematis, all the species have spreading sepals and glabrous stamens, except for Clematis pinnata, which has ascending sepals and usually hairy stamen filaments. In Sect. Lasiantha with 2 species restricted to western U. S. A., C. lasiantha has glabrous stamens, while C. paucifiora has stamens hairy on fliaments. In Sect. Naraveliopsis with spreading sepals,the majority of species have glabrous stamens, but one species, C.liboensis, endemic to Guizhou Province, China, has hairy stamens. These facts just mentioned indicate that the evolution of sepals and stamens took place in several lineages independently in Clematis. (3) In Clematis, glabrous stamens of C.apiifolia, C.grata, and C.montana with linear filaments and oblong anthers, are similar to those of Caltha, Calathodes, Trollius, and Anemone. Thus, the linear filaments and oblong anthers are considered primitive characters in Clematis. On the other hand, lanceolatelinear filaments of C. tangutica and C. aethusifolia or oblanceolate -linear filaments of C. courtoisii and C. loureiriana and linear anthers of C. meyeniana and C. uncinata, and narrow-linear anthers of C. courtoisii and C. lanuginosa are considered advanced ones. In ease of stamens with hairs, stamens of C. henryi with densely villous filaments and those of C. kweichowensis with both filaments and anthers densely pubescent show more advanced condition than those of C. pinnata, C. heracleifolia, and C. tangutica, with sparsely puberulous filaments and glabrous antbers(Fig. 1 ). (4)The pedunculate, 2-bracteate dichasial cyme with several flowers may represent the primitive type of inflorescences in Clematis. Manyflowered panicle-like cymes as in C.gouriana and C. tsaii, or few-l-flowered cymes as in C. henryi and C. repens, and cymes lacking peduncles and bracts as in C. montana and C. pogonandra are all considered advanced. Besides, the fact that flowers arise from axillary buds of old branches shows also an advanced condition. (5)Sect. Clematis subsect. Pinnatae, with leaflets, inflorescence ramification, and stamens similar to those of C. heracleifolia, is considered intermediate between Sect. Clematis and Sect. Tubulosa. (6) Subsect. Clematis and Subsect. Rectae, and Subsect. Connatae and Subsect. Crispae are so closely related to each other respectively that it is difficult to ascertain the systematic position of some intermediate species between the two subsections of each pair in the absence of seedlings. So, in the present paper, following the classification of Clematis proposed by Tamura in 1967, I put Subsect. Clematis and Subsect. Rectae in Sect. Clematis, and Subsect. Connatae and Subsect. Crispae in Sect. Viorna. (7)According to the evolutionary tendencies mentioned above, a realignment of the sections and the infrasectional taxa of the Chinese Clematis is made. (8) Six subsections, 6 serise, 2 species, and 4 varieties are described as new, and 5 new combinations, 4 new ranks, and 2 new names are given. (9)The specific rank of C. tenuipes W.T. Wang, reduced to varietal renk in 1980, is restord. C. taiwaniana Hayata, reduced to synonomy of C. grata Wall. in 1991, is considered distinct from the latter in hairy adaxial surface of sepal and narrower achene with tapering apex. C. kerriana Drumm. & Craib and C. laxipaniculata Pei are proved to be conspecific to C. subumbellata Kurz and reduced to syn-onymy.
  • MA Qing-Wen, WANG Yu-Fei, CHEN Yong-Zhe, LI Cheng-Sen
    J Syst Evol. 1998, 36(2): 173-177.
    Coniopteris tatungensis is a common element in the Jurassic floras. This paper deals with new collection of C. tatungensis from Beijing and reports the details of the reproductive feature of this plant observed by SEM. The taxonomical assignment and geographical distribution of C. tatungensis are discussed also in this paper. In C. tatungensis Sze., fronds at least 2~3 times pinnate, with main rachis slender. Pinnae alternate, linear to linear-lanceolate . The first pair of pinnules nearly opposite, others becoming alternate. First pinnule on the acroscopic side of the penultimate pinnae well developed and divided into 2~ 3 lobes, while the first pinnule on the basiscopic side obviously weak, much smaller and narrower, usually divided into 1~2 lobes. Reproductive fronds fully or partly fertile, the latter with first pinnules on the acroscopic side bearing fewer sori. The lamina of pinnule strongly reduced bearing an elliptical sorus distally. Number of sori mostly 1 per pinnule, but often 2 ~3 at the basal part of penultimate pinnae. Indusia cup-shaped. Sori containing at least 12 sporangia. Sporangia shortly stalked, not all at the same age in a sorus. Sporangia rounded to ellipsoidal. Annuli not complete, nearly vertical, consisting of about 15~20 thicked cells.Spores rounded-triangular, trilete, laesurae reaching almost to equator.
  • TANG Yan-Cheng, LU An-Ming
    J Syst Evol. 1998, 36(2): 178-192.