Table of Contents

14 January 2014, Volume 52 Issue 1
Cover illustration: Wangia saccopetaloides (W. T. Wang) X. Guo & R. M. K. Saunders. Left, flower with short outer petals and longer inner petals. Top right, fruit with torulose monocarps. Middle right, dissected monocarp showing uniseriate seed arrangement. Bottom right, pollen grain showing rectangular shape and depressed cryptoapertures. Photographs by Yun-Hong TAN (all except bottom right) and Xing GUO (bottom right). See GUO et al., pp. 1–15 in this issue.
    Research Articles
  • Xing GUO, Jing WANG, Bine XUE, Daniel C. THOMAS, Yvonne C. F. SU, Yun-Hong TAN, Richard M. K. SAUNDERS
    J Syst Evol. 2014, 52(1): 1-15.
    The systematic position of two enigmatic Annonaceae species from China, Desmos saccopetaloides (W. T. Wang) P. T. Li and Desmos yunnanensis (Hu) P. T. Li, has been controversial, with both species having been transferred between several different genera within subfamilies Annonoideae and Malmeoideae. Phylogenetic analyses of eight chloroplast regions (matK, ndhF, ndhF-rpl32, psbA-trnH, rbcL, rpl32-trnL, trnL-F, and ycf1; ca. 9.2 kb, 66 taxa) unambiguously placed D. saccopetaloides in a subclade of tribe Miliuseae, nested among the genera Monoon, Neo-uvaria, Phaeanthus, Sageraea, and Stelechocarpus. This relationship was also supported by endosperm rumination patterns in the seed; other morphological characters furthermore indicated that D. saccopetaloides has closer affinities withMonoon, Neo-uvaria, and Phaeanthus rather than either Sageraea or Stelechocarpus. Desmos saccopetaloides is distinguished from these genera by its leaf-opposed inflorescences, sepaloid outer petals, saccate inner petals with basal glandular tissue, moniliform monocarps with uniseriate seeds, and rectangular disulculate pollen with two “cryptoapertures.” On the basis of the combined molecular phylogenetic and morphological data, we propose a new genus, Wangia, to accommodate D. saccopetaloides. The molecular phylogenetic analyses furthermore indicated that D. yunnanensis belongs to the genus Dasymaschalon: examination of the type collections revealed that it is conspecific with Dasymaschalon obtusipetalum, although the combination Dasymaschalon yunnanense has nomenclatural priority.
  • AJ HARRIS, Monica PAPEŞ, Yun-Dong GAO, Linda WATSON
    J Syst Evol. 2014, 52(1): 16-34.
    Past climates experienced by fossil plant species have often been inferred based on the environmental requirements of their evolutionarily nearest living relatives (NLR). Here we have combined paleoclimatic estimation using NLRs with ecolological niche modeling (ENM) and have demonstrated the combined approach by inferring the Eocene environment of Aesculus L. (Hippocastanoideae, Sapindaceae), a genus of woody eudicots with extant species generally preferring temperate climates. Specifically, we applied ENM-NLR to four Eocene floras in which Aesculus fossils are known to occur: McAbee and Princeton (British Columbia), Republic (Washington State), and Spitsbergen (European Arctic Circle). Additionally, we used ENM-NLR to estimate whether paleoenvironmental conditions were suitable forAesculus at a fifth flora, Copper Basin (Nevada), where the fossil record of the genus is less clear. We generated models for all NLRs in Genetic Algorithm for Rule Set Production using georeferenced data from the Global Biodiversity Information Facility and Bioclim environmental parameters. For each fossil flora, the best models of individual NLRs were summarized into composite community models, which were taken to represent climatically analogous modern communities and used to infer the paleoclimates of the fossil localities. Our results are generally consistent with previous studies that used other methods to estimate paleoclimates and suggest that McAbee, Princeton, Republic, and Spitsbergen had temperate environments. For the Copper Basin flora, our results show ranges of environmental variables that may be too broad for predicting whether Aesculus was present. Our study appears to be the first to combine the NLR approach and ENM to infer paleoclimates.
  • Da-Yong ZHANG
    J Syst Evol. 2014, 52(1): 35-39.
    A recent model by Currat et al. indicates that when one species colonizes an area already occupied by a closely related species, massive introgression of neutral genes should take place primarily in the direction from the local to the invasive species. Here, I show that this model relies on an assumption that might not capture the true dynamics of how species exchange migrants during admixture. As an alternative, I formulate a new model, based on a different and perhaps more biologically realistic assumption of interbreeding, that demonstrates symmetric introgression as compared to the large and asymmetric introgression predicted by the original model. The new model indicates that asymmetry is not a default property of introgressions, thus necessitating alternative explanations for the common observation of massive asymmetric introgression including sex-biased dispersal.
  • Jianhua LI, Jin-Huo JIANG, Cheng-Xin FU, Shao-Qing TANG
    J Syst Evol. 2014, 52(1): 40-50.
    Previous molecular phylogenetic studies of Fabaceae indicated that species of Wisteria, an intercontinental disjunct genus between eastern Asia and eastern North America, formed a clade derived from within Callerya. However, interspecific relationships were not well resolved or supported. In this study, we used sequences of the nuclear ribosomal DNA internal transcribed spacer region and the chloroplast gene matK to examine interspecific relationships and explore implications of the phylogeny for the systematics and biogeography of Wisteria. Our results showed that Wisteria with deciduous leaves and racemose inflorescences formed a strongly supported clade derived from within the paraphyletic Callerya. Afgekia was also found to be included within Callerya. Therefore, our data support the merger ofAfgekia, Callerya, and Wisteria. The phylogenetic pattern suggested that the deciduousness in Wisteria may be a derived trait likely in response to temperate climate, and the racemose inflorescences in the AfgekiaCalleryaWisteria clade may have evolved from panicles. Our study also provided strong support for the sister relationship of the North American and eastern Asian species of Wisteria. In the Asian clade, Wisteria brachybotrys Siebold & Zucc. of Japan was sister to the clade containing W. floribunda (Willd.) DC of Japan and Korea, and W. sinensis (Sims) Sweet of China. However, our data offered weak support for the sister relationship ofW. floribunda and W. sinensis. Our divergence time and biogeographic analyses suggested that the eastern Asian–North American disjunction in Wisteria may have occurred through a dispersal event in the middle Miocene (13.4 Mya) from the Old World to the New World across the Bering land bridge followed by vicariance in the late Miocene (6.8 Mya). This study added another example to the “out of Asia” migration for the eastern Asian–eastern North American disjunction.
  • Jin CHENG, Lei XIE
    J Syst Evol. 2014, 52(1): 51-67.
    Caltha is a widely distributed genus in the buttercup family (Ranunculaceae) showing interesting distribution patterns in both hemispheres. Evolutionary history ofCaltha was examined by means of phylogenetic, molecular dating, and historical biogeographic analyses with a more comprehensive sampling than previous studies. The internal transcribed spacer from the nuclear genome and trnL-F and atpB-rbcL regions from the plastid genome were used and analyzed using parsimony and Bayesian methods. Divergence time was estimated using Bayesian dating analyses with multiple fossil calibrations. Historical biogeography was inferred using the Bayes-DIVA method implemented in RASP. We obtained a well-resolved and well-supported phylogeny within the Caltha lineage. Caltha natansPall. diverged first from the genus and the other species grouped into two clades. Our expanded sampling scheme revealed a complicated evolutionary pattern in theC. palustris complex. Caltha sinogracilis W. T. Wang was resolved to be a member of the C. palustris complex, rather than closely related to C. scaposa Hook. f. & Thomson. Caltha rubriflora B. L. Burtt & Lauener was also revealed to be not just a red-flower form of C. sinogracilis. The diversification of the genus began at 50.5 mya (95% high posterior density: 37.1–63.9 mya), and its ancestral range was very probably in the Northern Hemisphere. The South American species may derive from western North American ancestors that dispersed along the western American Cordillera during the Cenozoic era. The vicariance model of the Southern Hemisphere species proposed by a previous study was rejected in this study.
  • Steven R. MANCHESTER, Peter W. FRITSCH
    J Syst Evol. 2014, 52(1): 68-74.
    We are compelled to sink the European fossil fruit genus Sphenotheca Kirchheimer into extant Symplocos based on newly recognized morphological and anatomical similarity with the fruits of extant Symplocos tanakae Matsum. of Japan and Symplocos henryi Brand of SW China. Recognition of Symplocos incurva (Kirchheimer) comb. nov. and Symplocos bornensis (Mai) comb. nov. increases the number of late Paleogene and Neogene European species of Symplocos to 13. The close relationship between this fossil species and extant species of the Symplocos lucida clade of eastern Asia suggests that migration of this group between Europe and Asia was facilitated by the closure of the Turgai Strait that commenced during the Oligocene.
  • Jannathan MAMUT, Bing LI, Dun-Yan TAN
    J Syst Evol. 2014, 52(1): 75-83.
    Protogyny and delayed selfing are two mechanisms in facilitating outcrossing and increasing female and male function in self-compatible plant species. However, both mechanisms are rarely reported within a species. Here, we investigated pistil and stamen development, breeding system, and pollination biology of the desert herb Zygophyllum macropterum C. A. Mey. by use of field observations and manipulation experiments. Our primary aim was to assess whether protogyny and delayed autonomous self-pollination occurred in this species. Zygophyllum macropterum is a spring flowering species with a floral longevity of approximately 3 days, including the female stage and the bisexual stage. Movement herkogamy occurred during both stages. The stigma was receptive when it was exposed from the corolla. The time of first anther dehiscence was approximately 12 h after stigma exposure. These results indicated that Z. macropterum is protogynous. Different pollination treatments showed that this species is self-compatible and can self-pollinate autonomously. Time of first dehiscence of anther overtopping the stigma was approximately 16 h after stigma exposure, suggesting that autonomous self-pollination can occur in middle-late anthesis, and thus can be defined as delayed autonomous self-pollination. Anthophora plumipes Pallas. was the only pollinator of Z. macropterum. The unfavorable spring desert environment and the small corolla mouth diameter at the female stage would limit pollinator activity and thus lead to failure of outcrossing and occurrence of delayed self-pollination. Therefore, both protogyny and delayed selfing play an important role in enhancing the opportunity for outcrossing and reproductive assurance of Z. macropterum in the spring desert environment.
  • Li-Hui ZHANG, Yan-Wen ZHANG, Xing-Nan ZHAO, Sheng-Jun HUANG, Ji-Min ZHAO, Yun-Fei YANG
    J Syst Evol. 2014, 52(1): 84-91.
    Varied nutrient sources can influence the plasticity of reproductive strategies in monoecious species differently. We examined the plasticity of sexual and clonal reproductive components in distinct nutrient sources in a monoecious species, Sagittaria graminea Michx. The results showed that for aboveground reproductive components, in rich-phosphorus and low-nitrogen conditions, the species produced more male flowers, whereas female flowers did not significantly increase in number compared to low-phosphorus and low-nitrogen conditions (control). In rich-nitrogen and low-phosphorus conditions, the species produced more flowers, particularly female, and more seeds, compared to the control conditions. In the rich-nitrogen and rich-phosphorus conditions, plants increased male flowers, female flowers, total flower number, synchronously, as well as seed production. For the belowground reproductive components, in the rich-phosphorus conditions, the plants produced bigger corms than in the rich-nitrogen and control conditions, which further enhanced their competitiveness against companion species. In rich-nitrogen conditions, the plants produced more medium and small corms, and relatively more and longer stolons, which were useful in expansion and invasion of more space. Furthermore, the species displayed trade-off relationships between the aboveground and belowground reproductive components in unbalanced nutrient conditions (add-N or add-P). However, in low nutrient levels (control) or in nutrient abundant (add-N + P) conditions, there were no significant trade-off relationships between the aboveground and belowground reproductive components, based on quantities.
  • Li JI, Shu-Lian XIE, Jia FENG, Le CHEN, Jie WANG
    J Syst Evol. 2014, 52(1): 92-100.
    Four endemic Batrachospermaceae species in China, Batrachospermum hongdongense Xie & Feng, Batrachospermum longipedicellatum Hua & Shi, Kumanoa curvata (Shi) Vis et al., and Kumanoa intorta (Jao) Entwisle et al., were analyzed with multilocus data in order to assess their phylogenetic placement. Multilocus molecular data from one nuclear gene (the ribosomal SSU), one chloroplast gene (rbcL), and two mitochondrial genes (COI and the cox2-3 spacer) as well as morphological studies were used to determine the phylogenetic relationships of these endemic species within the Batrachospermales. Batrachospermum hongdongense and B. longipedicellatum had previously been placed in Batrachospermum section Batrachospermum, but based on the data from this study they should be transferred into section Helminthoidea. Kumanoa curvata and K. intorta clearly belong to the newly established genus Kumanoa.
  • Peng ZHAO, Gui-Fang ZHAO, Shuo-Xin ZHANG, Hui-Juan ZHOU, Yi-Heng HU, Keith E. WOESTE
    J Syst Evol. 2014, 52(1): 101-111.
    Random amplified polymorphic DNA (RAPD) was used as a molecular tool to evaluate genomes of butternut (Juglans cinerea), Japanese walnut (Juglans ailantifolia), black walnut (Juglans nigra), Persian walnut (Juglans regia), Manchurian walnut (Juglans mandshurica), and an interspecific hybrid (J. ailantifolia × J. cinerea) for species-specific markers. Forty decamer RAPD primers generated 668 RAPD amplicons that were used to characterize bulked DNA pools of butternut, Japanese walnut Persian walnut, Manchurian walnut, and buartnut hybrids and to identify genomic regions found only in Japanese walnut or Manchurian walnut. The amplicons ranged in size from 150 to 2068 bp; sixty-five were polymorphic (9.7%) among the six taxa evaluated. Thirty-eight amplicons were unique to Japanese walnut and buartnut hybrids but absent in butternut. The RAPD markers we used were not sufficiently polymorphic to characterize intraspecific variability within Japanese walnut, butternut, or their hybrids. However, they can be used to identify hybrids based on the presence of introgressed genomic fragments inherited from Japanese walnut. They may also be useful for distinguishing whether Japanese walnut or Manchurian walnut was the parent of a hybrid lineage. The results confirmed that some hybrids can be distinguished by their morphology, and genetic similarity based on RAPDs appears to reflect known pedigree information. These RAPD markers may prove useful for conservation of butternut, an endangered North American species. These results also may prove useful for the molecular identification of species and species hybrids within Juglans.
  • Bo-Ling LIU, Hong-Bo PANG, Xia YANG, Yin-Zheng WANG
    J Syst Evol. 2014, 52(1): 112-123.
    In Asterids, specific expression of CYC-like genes in the corresponding regions promotes or reduces dorsal petal growth and aborts stamen development. In Rosids, however, the reduced or enlarged dorsal petals are not accompanied by the abortion of stamens, which implies that the function of CYC-like genes in regulating petal growth and stamen development might be independently recruited. To address this, we investigated the function of the PhCYC1C gene in Primulina heterotricha Y. Dong & Y. Z. Wang on petal growth and stamen development by overexpressing it in two different transformation systems, that is, Arabidopsisbelonging to Rosids and tobacco located in Asterids. The results showed that overexpression of PhCYC1C reduced petal sizes in both tobacco and Arabidopsistransgenic plants mainly by repressing cell expansion, indicating its conserved function in determining petal growth between Asterids and Rosids. However, the fertility of both tobacco and Arabidopsis stamens was not affected at all. Given that strong expression signals of PhCYC1C are detected in both tobacco andArabidopsis stamens and CYC-like genes actually function to repress stamen development in Lamiales, we suggest that the CYC-like gene-associated regulatory network for controlling stamen development might have not established in Rosids as well as in early evolution of Asterids, but evolved as Asterids proceeded further. Our results provide valuable information on the conservation of CYC-like genes' function in controlling corolla asymmetry and the divergence of their function in determining stamen abortion in angiosperms.