Table of Contents
  • Volume 37 Issue 4

      
      Research Articles
    • YING Tsun-Shen
      1999, 37 (4): 305–350
    • HONG De-Yuan, PAN Kai-Yu
      1999, 37 (4): 351–368
      The taxonomical history of the woody group(peonies) in the genus Paeonia is reviewed in the present paper. The group is endemic to China, but Paeonia suffruticosa is commonly cultivated throughout the north temperate region and has long been known as “the King of Flowers” in China. However, the taxonomy of the group had been neglected before the 1990' s. Since 1990, a number of new species and subspecies have been published. With the support from the National Geographic Society, the senior author of the present paper and his coworkers have made expeditions to all parts of the distribution area of the group, visited all the type localities and sampled a total of 64 populations. Based on the character analysis and examination of the type specimens or photos, each taxon is reviewed with its name checked nomenclaturally, and finally the taxonomy of the whole group is revised. As a result, eight species, three of which each contains two subspecies, are recognized. They are Paeonia suffruticosa Andrews subsp. suffruticosa and subsp. yinpingmudan D. Y. Hong, K. Y. Pan et Z. W. Xie, P. jishanensis T. Hong et W. Z. Zhao, P. qiui Y. L. Pei et D. Y. Hong, P. ostii T. Hong et J. X. Zhang, P. rockii (S. G. Haw et L. A. Lauener )T. Hong et J. J. Li subsp. rockii and subsp. taibaishanica D. Y. Hong, P. decomposita Hand.-Mazz. Subsp. decomposita and subsp. rotundiloba D. Y. Hong, P. delavayi Franeh. and P. ludlowii (Stern et Taylor)D. Y. Hong. P. baokangensis Z. L. Dai et T. Hong and P. yananensis T. Hong et M. R. Li are considered as hybrids between P. rockii and P. qiui and between P. rockii and P. jishanensis respectively. In addition, the reduction of a number of names recently published to synonyms is explained.
    • ZHOU Zhe-Kun
      1999, 37 (4): 369–385
      The fossil history of the Fagaceae from China and its systematic and biogeographic implications are discussed based on revisionary studies of the fossil records. No creditable macrofossil record of the Fagaceae exists in the Cretaceous deposits and all the Cretaceous microfossil reports remain equivocal and require further study. The Paleocene fossils show the appearance and diversification of the two groups corresponding to the subfamilies Fagoideae and Castaneoideae sensu Nixon. By the Eocene, all modern genera had been present. The oldest fagaceous fossils represent subfamily Fagoideae with affinities to the extant genus Trigonobalanus. The leaf fossil genus Berryophyllum, with affinities to Quercus subg. Cyclobalanopsis, has been documented by the early Eocene and might have occurred earlier than other fossils assignable to Quercus. The appearance of evergreen sclerophyllous Ouercus with entire leaves might have occurred earlier than those with toothed leaves. Deciduous, urticoid-leaved oak fossils (Quercus subg. Quercus sect. Quercus) had not appeared until the Miocene. Fossil equivalents of Trigonobalanus, Castanopsis and Lithocarpus had occurred in Europe and North America by the early Tertiary, suggesting that continuous distributions were achieved via the northern hemisphere land bridges. Three groups of evergreen sclerophyllous oaks of apparent close phylogenetic relationships occurred in the Hengduan mountains, the Mediterranean area and northwestern North America. Their fossil forms have become dominant elements of those vegetation zones since the Miocene. A shared fossil history indicates a possible biogeographic boundary formed by the ancient Mediterranean. The evidence suggests that the oaks might arrive in North America during two distinct geologic periods: evergreen sclerophyllous entire-leaved oaks appeared by the Early Tertiary, whereas thedeciduous oaks with urticoid leaves appeared in the Late Tertiary.
    • ZHOU Yong-Hong, YANG Jun-Liang, YAN Ji, ZHENG You-Liang
      1999, 37 (4): 386–393
      Morphological comparison, cytogenetic study and fertility analysis of Hystrix duthiei (2n = 28) from China, Hystrix longearistata (2n= 28) from Japan and their artificial hybrids were carried out. Morphologically H. duthiei was similar to H. longearistata. H. longearistata had longer lemma awn, wider leaf and 2~3 florets per spikelet, while H. duthiei had 1~2 florets per spikelet. These two taxa can be easily crossed. Fl hybrids showed very high degree of bivalent pairing (13~14 bivalents) at the metaphase- I of meiosis. No multivalents were found. The fertility of pollen and seed set of the parents were normal, while the Fl hybrids were of only partial fertility. H. longearistata was closely related to H. duthiei. They should be included in the same species. Because of the differences of their distributions and habitats, some morphological divergency and a little sterility barrier have had appeared between them. It is reasonable to treat Hystrix longearistata as a sub-species of Hystrix duthiei .
    • WANG Yan-Hong, MA Jin-Shuang, LIU Quan-Ru
      1999, 37 (4): 394–402
      In this paper, eight species of the genus Euphorbia L. were cytologically studied. The three species of the subgenus Chamaesyce Raf., E. hirta, E. humifusa and E. hypericifolia, had chromosome numbers of 2n = 18, 22 and 32, with their basic chromosome numbers being x = 9, 11 and 8 respectively. The two species of the subgenus Poinsettia (Grah.) House. E. dentata, with 2n=28, a tetraploid, and E. cyathophora, with 2n= 56, a octoploid, had both the basic chromosome number of x= 7. The three species of the subgenus Esula Pers, E. lathyris, E. helioscopia and E. hylonoma, had chromosome number of 2n= 20, 42 and 20, with their basic numbers being x= 10, 7 and 10 respectively. The basic chromosome number of x = 8 is new for E. hypericifolia, in which x = 7 was previously reported. This indicates that this species had both ploidy(2n = 4x = 28, 8x = 56) and dysploidy(x = 7, 8) variations. In E. dentata, there occurred also ploidy variation (2n = 2x, 4x and 8x). A tetraploid cytotype of E. esula was found in China, its diploid cytotype and hexaploid cytotype being previously reported in North America, the Iberian Peninsula and some other European areas. Based on our results and those previously reported, we support the viewpoint that x=10 may be the original basic chromosome number of Euphorbiaand discuss the role of polyploidy and dysploidy in the speciation and evolution of this genus
    • CAO Tong, FU Xing, GAO Chien, WU Yu-Huan, R.J.Belland, D.H.Vitt
      1999, 37 (4): 403–406
      The luminous moss, Schistostega pennata (Hedw.)Web. et Mohr belonging to the family Schistostegaceae was discovered from Changbai Mountain, Northeast China. The morphological characteristics, ecology and distribution of this species are described and dis-cussed.
    • WANG Jian-Bo, ZHANG Wen-Ju, CHEN Jia-Kuan
      1999, 37 (4): 407–416
      Nuclear rRNA genes (rDNA) in angiosperms are arranged in long tandem repeat ing units, much like those of other higher eukaryotes. Owing to rapid concerted evolution, the repeat units have homogenized or nearly so in most species. The internal transcribed spacer (ITS) of nuclear rDNA is composed of ITS1 and ITS2, which are seperated by 5.8S rDNA. The two spacers, ITS1 (187~298 bp) and ITS2 (187~252 bp), can be readily amplified by PCR and sequenced using universal primers. The sequences contain many vari able sites and potential informative sites among related species, and have been proven to be a useful molecular marker in phylogenetic and evolutionary studies of many angiosperm taxa. It can be used not only in classification and phylogenetic inferences at the levels of family, subfamily, tribe, genus and section, but also in reconstruction of reticulate evolution and de tection of the speciation via hybridization and polyploidization. But this region may not be useful for resolving phylogenetic relationships among families or taxa of higher hierarchy ow- ing to the rapid variation of the ITS sequences.
Editors-in-Chief
Song Ge
Jun Wen
Impact Factor
2.779
JCR 2019 IF ranking: 56/234 (Plant Sciences, top 23.72%, Q1 quartile)
Journal Abbreviation: J Syst Evol
ISSN: 1674-4918 (Print)
1759-6831 (Online)
CN: 11-5779/Q
Frequency: Bi-monthly

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