Table of Contents

18 March 2007, Volume 45 Issue 2
    Research Articles
  • LI Xiao-Xian, ZHOU Zhe-Kun
    J Syst Evol. 2007, 45(2): 113-133.
    Two chloroplast (matK and rbcL), and one nuclear (18S) genes from 86 families, 126 genera, and 151 species of angiosperms (including 58 families, 86 genera, and 101 species of monocots), representing all major lineages of monocots and the basal angiosperms, were analyzed using parsimony methods. The eumagnoliids composed of Magnoliales, Laurales, Canellales, and Piperales appear as sister to the whole monocots. The monophyly of monocots receives 98% bootstrap support in the combined analyses of three genes. The monophylies of nine clades of monocots (Alismatales s.l., Dioscoreales, Pandanales, Asparagales, Liliales, Arecales, Poales, Zingiberales, and Commelinales) and six clades of other angiosperms (Nymphaeales, eudicots, Magnoliales, Laurales, Piperales, and Canellales) were supported in the strict consensus tree of combined analyses. The results showed that the genus Acorus is the basalmost clade among extant monocots, followed by Alismatales s.l. (including Araceae and Tofieldiaceae). Petrosaviaceae are placed as a sister group of the clade comprising the Dioscoreales-Pandanales clade, Asparagales, Liliales and commelinoids. The sister-group relationships are strongly supported between Petrosaviaceae and the remaining monocots (except for Acoraceae and Alismatales s.l.), between Dioscoreales and Pandanales, and between Commelinales and Zingiberales in the combined analyses of two genes and three genes. However, the phylogenetic relationships among Asparagales, Liliales and commelinoids are still uncertain in current analyses. In commelinoids, the relationships of Arecales and Poales still need more research in future. Furthermore, it is noteworthy that the sister relationship between Petrosaviaceae and the remaining monocots (except for Acoraceae and Alismatales s.l.) and the monophylies of Dioscoreales and Asparagales were strongly supported with bootstrap values more than 90%, which generally received bootstrap values less than 50% in the previous studies. Considering the special position of Acoraceae and Petrosaviaceae, we support the taxonomical treatment of Acoraceae and Petrosaviaceae in their own order Acorales and Petrosaviales.
  • ZHU Hua, MA You-Xin, YAN Li-Chun, HU Hua-Bin
    J Syst Evol. 2007, 45(2): 134-166.
    This paper aims to illustrate the distribution patterns of generic-level elements of Chinese seed plants and their correlations to climatic and geographic gradients. A total of 204 regional floras covering all of China were used to make distribution maps for all seed plant genera using GIS (Geographic Information Systems) technology. Climatic gradients were based on data sets from 841 meteorological stations throughout China. Definitions for floristic distributional patterns were based upon the work of Prof. Z. Y. Wu. Most of these floristic distributional patterns were strongly correlated with the geographic gradients in climate, except for cosmopolitan, cultivated and invasive genera. Tropical genera form a large fraction of the total genera (ranging from 0.84% to 94.38% in the regional floras) with the highest proportion in southern Yunnan and Hainan Island. Tropical genera occur predominantly in southern China of <30? N latitude and decreased with increasing latitude, as would be expected. Interestingly, the disjunct Tropical Asia and Tropical America distribution were not restricted to southern latitudes. Temperate genera account for 5.1% to 98.83% of the total genera in regional floras with the highest proportion in the province of Xinjiang. Most of these genera followed geographic gradients in climate as expected (temperate genera conspicuously dominate the landscape at higher latitudes), except the East Asian and North American disjunct distribution, Eastern Asian distribution and Chinese endemic distribution. Generally, most plant genera demonstrated some correlation with climatic and geographic gradients. The most important gradients were those of annual air temperature and precipitation. A small fraction did not demonstrate significantly particular pattern: “Cosmopolitan”, “East Asian and North American disjunct”, “Eastern Asian” and “Chinese endemic” distributions. The North Temperate distribution had the highest correlation with mean annual air temperature and precipitation. These results demonstrate that the Chinese seed plant genera correspond well to recognized vegetation zones and floristic regions, providing further support for the current phytogeographic definitions.
  • ZHANG Xin-Hua, XIA Nian-He
    J Syst Evol. 2007, 45(2): 167-190.
    Leaf architectural and morphological characters of 28 taxa from Michelia, Paramichelia and Tsoongiodendron (Magnoliaceae sensu stricto, subtribe Micheliinae) were examined to gain a better understanding of the intergeneric relationships and the systematic positions of some species within Michelia. The taxa examined, all of which have simple leaves with entire margins and camptodromous pinnate venation, varied in their secondary venation, which was brochidodromous or brochidodromous to eucamptodromous, the mixture of simple and composite intersecondary veins, percurrent to reticulate tertiary veins. Dendroid veinlets were recorded for the first time in Michelia species. Phenetic analyses of leaf architectural characters and morphological characters suggested that Paramichelia and Tsoongiodendron are grouped together and merged in the Michelia, and these characters provide useful taxonomic information for division of sections in Michelia. In addition, systematic positions of some species in Michelia are discussed.
  • YANG Zhi-Rong, LIN Qi,
    J Syst Evol. 2007, 45(2): 191-206.
    The wood anatomy of 21 collections of 7 species within Kadsura Kaempf. ex Juss. and 14 collections of 8 species of Schisandra Michx., representing a large proportion of two genera in Schisandraceae, was investigated using light microscopy and scanning electron microscopy. Several features in the secondary xylem, such as types of vessel elements, arrangement of vessel-ray pitting, types of ray and shape of the body ray cells, show consistent characteristics at the family level, which support the view that Schisandraceae represents a monophyletic group. The antiquity of Schisandraceae is supported by the presence of single vessel, scalariform perforation plates with many bars, scalariform vessel pitting and heterogeneous rays. A few apomorphic character states, such as simple perforation plates, helical thickenings in secondary walls of vessels and septate fibers, can be found in Schisandraceae, which make this family a mosaic with both plesiomorphic and apomorphic character states. A UPGMA analysis shows that species of Kadsura and Schisandra overlap in a dendrogram, which is congruent with the results from molecular data and indicates that the two genera are closely related, perhaps originating from the same ancestor. The wood anatomy evidence also confirms a close relationship between Schisandraceae and Illiciaceae, and does not support separation of Schisandraceae from Illiciales as Schisandrales.
  • ZHOU Song-Dong, HE Xing-Jin*, YU Yan, XU Jie-Mei
    J Syst Evol. 2007, 45(2): 207-216.
    In this paper, karyotypes from twenty-one populations in eight species of Allium section Rhiziridium from China were investigated. The karyotypes of two species, A. eduardii and A. flavovirens, and the hexaploidy karyotype of A. strictum are reported for the first time. By studying karyotypes of this section in Allium, we hope to understand evolutionary mechanisms and relationships among the taxa in this section. We find that five species, A. eduardii, A. flavovirens, A. lineare, A. mongolicum and A. oreoprasum are diploid, and that their karyotypes are the 2A type of Stebbins. The two species, A. tuberosum and A. ramosum, are tetraploid and their karyotypes are also the 2A type. Four populations of the species A. strictum are hexaploid and their karyotypes are the 2B type. From the karyotype analysis we obtain the following results: (1) In this section, there are many polyploids and polyploid series. The variation in the chromosome number in this section is closely related to the evolution history of the species. Therefore polyploidization might be one of the important evolutionary mechanisms that has shaped species diversity in sect. Rhiziridium. (2) The satellite chromosomes are either subterminal or terminal chromosomes and satellites are located in the short arm. (3) It is suggested that A. strictum might represent an incipient species and has exploited a new niche through ployploidization. (4) The cultivated species A. tuberosum might be derived from the artificial naturalization of the wild diploid and tetraploid ancestors. The cultivated triploid species is suggested to have originated from the hybridization between the wild diploid and tetraploid ancestors, and its survival and widespread cultivation might have been achieved through asexual reproduction.
  • LI Yong-Quan, ZHANG Dian-Xiang
    J Syst Evol. 2007, 45(2): 217-226.
    The floral and pollination biology of Antidesma montanum was studied. The floral phenology, pollen-ovule ratio (P/O), pollen histochemistry, pollen viability, floral visitors and their behavior, and the sexual system were observed and determined. The observation is that Antidesma montanum is a dioecious species with a sexual ratio of ca. 1:1 during anthesis. Results were obtained as follows: (1) A male/female inflorescence consisted of 140.33±27.79/208.33±33.65 (n=6) small (diameter ca. 3.4 mm) light greenish yellow flowers; both male and female inflorescences lasted for ca. 7 days. (2) The longevity of a single flower of A. montanum was 2 days; pollen viability (MTT test) remained at a high level (>95%) after anthesis; the pollen was starchless; uncalibrated pollen/ovule ratio was 3333.33±607.18; a mesh-netted flower produced up to 0.34?0.03 ?L nectar with 3.69%?0.30% sugar equivalent. (3) The floral design and floral display were well adapted to fly pollination. (4) The effective pollinators were dipteran insects Chrysomya megacephala (Calliphoridae), Chrysomya sp., Drino sp. (Tachinidae), Spilogona sp. (Muscidae), and Mitroplatia sp. (Muscidae), which visited both male and female flowers for nectar. The sweet scent emitted during anthesis was a direct attraction to pollinators. No fruit set in bagged flowers indicated that there was no apomixis. No significant difference was found in fruit sets between flowers with open pollination (36.7%) and hand supplemental pollination (39.1%), suggesting that the fruit set was determined by its resource limitation. The correlations between fly pollination and the diclinous sexual systems, and between fly pollination and plants with small greenish yellow flowers were also discussed.
  • LIU Ming-Zhen, ZHOU Zhong-Ze, QIU Ying-Xiong, SUN Wei, DONG Xiang
    J Syst Evol. 2007, 45(2): 227-233.
    It has been debated whether two Polygonum species, P. cyanandrum Diels and P. forrestii Diels, should be transferred to Koenigia. In the present paper, nucleotide variations of the chloroplast atpB-rbcL noncoding spacer were examined for these two species and related representatives from the Polygonaceae. The atpB-rbcL spacer region varies among sampled species with a range from 753 to 902 bp, and the great variation in this region provides enough information for evaluating the phylogenetic relationships of the two investigated species. In contrast to the view that these two species belong to Polygonum, our phylogenetic analyses based on these molecular data showed that P. cyanandrum and P. forrestii were nested within a well supported clade including Koenigia islandica; the other three Polygonum species grouped with species of different genera. These results suggest that the two species should be transferred to Koenigia from Polygonum, and that phylogenetic relationships among Polygonum and related genera need to be further investigated with increased taxon sampling and gene markers. The resulting phylogeny is consistent with the previous suggestions based on pollen and chromosome investigations. The generic circumscription between Koenigia and Polygonum is also discussed in light of these results in combination with gross morphology.
  • DAO Zhi-Ling, CHEN Shao-Tian, JI Yun-Heng, LI Heng*
    J Syst Evol. 2007, 45(2): 234-238.
    Typhonium baoshanense Z. L. Dao & H. Li (Araceae: Areae), a new species from western Yunnan, China, is described and illustrated. This species differs mainly from other species of Typhonium by the presence of one to two rings of sterile male flowers above the fertile male flowers, and from T. blumei Nicolson & Sivadasan by a conic female part of the spadix, the appendix not being truncate at its base, and by the angustate limb of the spathe. The chromosome number of Typhonium blumei, which occurs in same area, is 2n=52, while the chromosome number of the new species is 2n=10. The chromosome number of the new species is the lowest in the family Araceae.
  • Vatsavaya S RAJU, C S REDDY, K G RAJARAO
    J Syst Evol. 2007, 45(2): 239-245.
    The status of the names, Physalis minima L. and P. maxima Mill. (Solanaceae), and their alleged presence on the Indian subcontinent are discussed. The issues of nativity and identity of Linnaean Physalis minima are long-debated while the use of the name P. maxima Mill. and its report from India are recent. The available evidence indicates that the name “P. minima L.” is misapplied to two different elements, viz., P. angulata L. and P. lagascae Roem. & Schult. The name Physalis minima L. may be rejected as nomen confusum, for which the paper provides the primary information. As on today, it is submerged under the synonymy of P. angulata L. The correct name for the widely known P. minima is P. lagascae. The name “P. maxima Mill.” applied to the escape and naturalized weed in the Indian subcontinent and elsewhere is to be substituted by P. pruinosa L., a name misapplied to P. grisea (Waterf.) M. Martínez.
  • LIU Nian, XIE Jian-Guang
    J Syst Evol. 2007, 45(2): 246-250.
    The morphological characters, distribution and type locality of Cycas taiwaniana are discussed in this paper. Cycas taiwaniana is only found in central-southern Fujian Province in China, with only one wild plant growing in Pinghe County. The type plant of the species still grows in front of CHEN Yuan-Guang Temple in Zhangzhou City.
  • ZHANG Li-Bing, YANG Qin-Er, Nicholas J. TURLAND, John MCNEILL
    J Syst Evol. 2007, 45(2): 251-255.
    The rules that govern scientific naming in botany (including phycology and mycology) are revised at Nomenclature Section meetings at successive International Botanical Congresses. The most recent edition of the International Code of Botanical Nomenclature (Vienna Code) embodies the decisions of the XVII International Botanical Congress held in Vienna in 2005 and supersedes the Saint Louis Code. This paper presents an account of the main differences between the two Codes, including those related with starting points, effective publication, valid publication, fossil plants, pleomorphic fungi, orthography, and the Appendices.