Table of Contents
  • Volume 59 Issue 3

    Cover illustration: Images represent the research target of Low et al., pp. 419–428 in this issue, on the typical tropical perennial species of Typhonium s.s. to understand the biogeographic origin of the Asian paleotropical flora by tracking its speciation and diversifi cation history. The genus was originated in Indochina during the early-middle Miocene, followed by extensive in situ speciation. The distribution and diversifi cation histories may have been triggered by the intensifi cation of the Asian [Detail] ...
      
      Issue Information
    • 2021, 59 (3): 1–4
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    • Editorial
    • Song Ge, Jun Wen
      2021, 59 (3): 417–418
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      Journal of Systematics and Evolution (JSE) established Awards of JSE Outstanding Papers in 2014 to recognize the most significant research published in JSE in a specific year (Ge & Wen, 2015). Since 2015, JSE has awarded papers each year in two categories (two papers in each): JSE Outstanding Papers and JSE Outstanding Papers by Young Investigators. The selection of the awards was based on votes and assessments from all 17 editors of the journal with the consideration of citation data from Thomson Reuters Web of Science and the impact on systematics and evolution. First authors who received their Ph.D. degree within 7 years are eligible for the JSE Young Investigators′ Awards. The winners of the Awards receive a certificate and a prize of $800 (JSE Outstanding Papers) or $500 (JSE Outstanding Papers by Young Investigators). Here we are delighted to announce the four winners of the Awards of JSE Outstanding papers selected from JSE publications in 2019 and we highlight the significance of these papers below.

      JSE Outstanding Papers for 2019:

      Rabah et al.:  Passiflora  plastome sequencing reveals widespread genomic rearrangements.

      As the largest genus within Passifloraceae, Passiflora L. consists of over 565 species with high diversified habits such as vines, lianas, shrubs, and small trees, and includes many economically important species that are cultivated worldwide (Rabah et al., 2019). Previous studies detected remarkable differences in plastomic changes in this genus and included Passiflora as one of several lineages that have highly rearranged plastomes. Despite these, knowledge about plastome organization in the genus remains limited. In this study, Rabah et al. (2019) completed the assembly of plastome sequences for 15 Passiflora species representing three subgenera and found that Passiflora plastomes had experienced multiple independent and shared inversions, gene and intron losses, and IR expansion and contraction, which resulted in a distinct plastome organization in each of the three subgenera. Remarkably, the authors show that Passiflora plastomes have experienced widespread genomic changes with the plastomes from each Passiflora subgenus being unique in terms of gene content, order, and size. The findings in this study, in conjunction with previous reports on other species, demonstrate the importance of using rare genomic changes for phylogenetic reconstruction with caution, because these events can occur independently in different lineages and may be unreliable phylogenetic characters.

      Martin-Bravo et al.: A tale of worldwide success: Behind the scenes of  Carex (Cyperaceae) biogeography and diversification.

      The sedge genus Carex L. has roughly 2000 species with a nearly cosmopolitan distribution and is among the three largest angiosperm genera in the world. Although substantial progress has been made on the phylogenetic history of the genus and the biogeography of particular groups, a global analysis of Carex biogeography and diversification is still lacking. Martín-Bravo et al. (2019) performed a comprehensive phylogenetic analysis by sampling two-thirds of the Carex species and all recognized sections in the genus. They revealed that Carex originated in the late Eocene in eastern Asia that was suggested to be both the cradle and museum of Carex diversification. Later synchronous diversification during the late Oligocene, that is, the “out-of-Asia” colonization features multiple asymmetric dispersals clustered toward present times among the Northern Hemisphere regions, with major regions acting both as source and sink (especially Asia and North America), as well as several independent colonization events into the Southern Hemisphere. Although some interesting questions regarding why Carex diversity is apportioned as it is across the globe remain to be answered, results arising from this work provide important new insights into understanding the biogeography and diversification of the genus, serving as the foundation for subsequent analyses of the patterns and mechanisms of Carex colonization and diversification across the globe.

      JSE Outstanding Papers by Young Investigators for 2019:

      Medina et al.: Phylogenomic delineation of  Physcomitrium  (Bryophyta: Funariaceae) based on targeted sequencing of nuclear exons and their flanking regions.

      Funariaceae are a diverse and cosmopolitan family of more than 250 species of annual mosses and constitute an appropriate case study to analyze recurrent morphological reversals because this family underwent a rapid diversification with many species exhibiting variable sporophyte complexities. This study assessed the phylogenetic relationships of five taxa with highly reduced sporophytes based on analyses of sequences of 648 nuclear loci. Based on inferences from concatenated data and concordance analysis of single gene trees, Medina et al. (2019) resolved that Physcomitrellopsis was nested within one clade of Entosthodon and indicated that Physcomitrella s. l. was a polyphyletic assemblage. Thus, they proposed a new monophyletic delineation of Physcomitrium, which accommodated the Physcomitrella and Aphanorrhegma species. These results will enhance our understanding of the sporophyte complexity and the evolution of the moss body as a whole.

      Jia et al.: First fossil record of  Cedrelospermum (Ulmaceae) from the Qinghai-Tibetan Plateau: Implications for morphological evolution and biogeography.

      Of three lines of evidence for exploring morphological evolution and biogeographical history of plants, fossils are the only evidence for the case of extinct species and thus records of fossil plants are key to understand plant migration, radiation, and extirpation that have shaped phytogeographic patterns in plants (Jia et al., 2019; Liu & Manchester, 2019). As an extinct genus in the elm family, Cedrelospermum Saporta has left abundant fossil records in North America and Europe but sparse records in Asia, which limits the explorations of the evolutionary history of the genus and the family Ulmaceae. Jia et al. (2019) reported the first fossil record of Cedrelospermum in the Qinghai–Tibetan Plateau (QTP) by describing well-preserved fruits (Cedrelospermum tibeticum sp. nov.) and a leaf (Cedrelospermum sp.) of Cedrelospermum. They showed that this genus occurred in this region during the late Oligocene and indicated that the central region of the QTP was phytogeographically linked with other parts of the Northern Hemisphere during the late Oligocene, thus supporting the hypothesis that Cedrelospermum migrated to Asia from North America by way of the Bering Land Bridge. Based on these observations, the authors discussed the significance of the new fossil findings for the morphological evolution and biogeographical history in general.

      We want to congratulate the authors of the above four awarded papers for their important contributions to systematics and evolution! We cordially invite the many colleagues in systematics and evolution to submit their first-rate research to JSE in the coming years.

    • Research Articles
    • Shook Ling Low, Chih‐Chieh Yu, Im Hin Ooi, Wichan Eiadthong, Alan Galloway, Zhe‐Kun Zhou, and Yao‐Wu Xing
      2021, 59 (3): 419–428
      The Asian paleotropical flora is characterized by abundance of endemic species, high biodiversity, and complex geological and climatic histories. However, the main driving mechanism underlying such high tropical biodiversity remains unclear. Hence, the present study aimed to investigate the biogeographic origin of the Asian paleotropical flora by tracking the speciation and diversification history of a typical tropical perennial, Typhonium sensu stricto (s.s.) (Araceae), using a time-calibrated whole-plastome phylogeny. In particular, we tested whether the Asian paleotropic region is a macroevolutionary source or sink. We observed that Typhonium s.s. originated in Indochina during the early–middle Miocene epoch, ca. 17.24 Ma (95% highest posterior density [HPD]: 12.83 ̶ 21.99 Ma). Most of the in situ diversification within the genus Typhonium s.s. has been underway since 14.73 Ma, with an accelerated lineage diversification at ca. 15−17 Ma, which may have been triggered by the intensification of the Asian monsoon system around the middle Miocene. Furthermore, the underground tuberous stem of Typhonium s.s. might have played an essential role in the adaptation to the seasonality caused by the monsoon in Indochina. Our results also suggested that peripatric speciation may be important in the diversification of T. trilobatum and T. roxburghii. This study provides a framework for studies in biogeography and evolution of the Asian paleotropical flora.
    • Typhonium s.s. originated in Indochina during the early–middle Miocene, ca. 17.24 Ma. Most of the in situ diversification within the genus Typhonium s.s. has been underway since 14.73 Ma, with an accelerated lineage diversification at ca. 15−17 Ma, which may have been triggered by the intensification of the Asian monsoon system around the middle Miocene epoch. Peripatric speciation might have played an essential role in the diversification process of widely disseminated species.
    • Jovani B. S. Pereira, Ana Maria Giulietti, Eder S. Pires, Marcele Laux, Maurício T. C. Watanabe, Renato R. M. Oliveira, Santelmo Vasconcelos, and Guilherme Oliveira
      2021, 59 (3): 429–441
      Although phylogenetic studies have revealed major clades, the deepest relationships in Isoetes remain unresolved. The use of next-generation sequencing provides enormous amounts of gene sequences, which allows not only clarification of the basal relationships but also rapid radiations. Plastomes of six key Isoetes species were annotated, revealing a total of 129 or 130 genes, depending on the species. Our phylogenomic analyses comprising representatives of all major clades yielded well-supported nodes and identical topologies using maximum likelihood and Bayesian inference. The phylogenetic reconstructions detangled the deep relationships in Isoetes and illuminated the more recent radiations in the genus. A basal dichotomy was found that grouped Isoetes spp. from Brazil and South Africa into a clade sister to the remaining Isoetes groups. Interestingly, I. andicola was found to be sister to the North American species complex. Genomic trait mapping analysis showed that the missing introns in the atpF and clpP genes were well conserved in two major clades. The absence of trnK-UUU was observed in the Brazilian tropical species and in I. velata. Among lycophytes, the gene trnR-CCG was missing only in I. eludens. In general, genomic traits such as the presence or absence of internal stop codons, a tRNA, and an intron were revealed to be conserved within groups, suggesting that these genomic traits might reveal vital information about the evolution of the genus. This study will contribute to understanding the diversification of Isoetes and the establishment of a better framework to address the evolutionary history of the genus.
    • Although phylogenies have revealed major groups, deep relationships in the genus Isoetes and the overall chloroplast genome architecture of its groups remain unclear. This study assembled chloroplast genomes for six species from distinct phylogenetic and taxonomic groups in Isoetes. Our study showed an overwhelming evolutionary stasis in the chloroplast genome of Isoetes. However, despite its conservative nature, the chloroplast genome provided enough DNA data to establish deep relationships in the genus. Furthermore, minor plastomic traits revealed to be conserved within groups, suggesting that they might reveal vital information about the evolution of the genus. Our study provides the most robust framework to understand the evolution of the chloroplast genome in Isotes.
    • Liang‐Min Liu, Xin‐Yu Du, Cen Guo, and De‐Zhu Li
      2021, 59 (3): 442–453
      The Brassicaceae is an economically and scientifically important family distributed globally, including oilseed rape and the model plant, Arabidopsis thaliana. Although growing molecular data have been used in phylogenetic studies, the relationships among major clades and tribes of Brassicaceae are still controversial. Here, we investigated the core Brassicaceae phylogenetics using 222 plastomes and 235 nrDNA cistrons, including 106 plastomes and 112 nrDNA cistrons assembled from newly sequenced genome skimming data of 112 taxa. The sampling covered 73 genera from 61.5% tribes and four unassigned genera and species. Three well supported lineages LI, LII, and LIII were revealed in our plastomic analyses, with LI sister to LII + LIII. In addition, the monophyly of the newly delimitated LII was strongly supported by three different partition strategies, concatenated methods under Bayesian and Maximum Likelihood analyses. LII comprised 13 tribes, including four tribes previously unassigned to any lineage, that is Biscutelleae as the earliest diverging clade and Cochlearieae as the sister to Megacarpaeeae + Anastaticeae. Within LII, the intertribal relationships were also well resolved, except that a conflicting position of Orychophragmus was detected among different datasets. In LIII, Shehbazia was resolved as a member of Chorisproreae, but Chorisproreae, Dontostemoneae, and Euclidieae were all resolved as paraphyletic, which was also confirmed by nrDNA analyses. Moreover, the loss of the rps16 gene was detected as likely to be a synapomorphy of the tribes Arabideae and Alysseae. Overall, using genome skimming data, we resolved robust phylogenetic relationships of core Brassicaceae and shed new light on the complex evolutionary history of this family.
    • Phylogenetic relationship of the core Brassicaceae based on the plastome-scale dataset, showing three well-supported lineages LI, LII, and LIII, with LI sister to LII +  LIII. The newly delimitated LII was strongly supported as monophyletic, with Biscutelleae as the earliest diverging clade, and in LIII, Shehbazia was resolved as a member of Chorisproreae. The present/absent genes (in blue/pink boxes) of this diagram indicated that the loss of the rps16 gene was likely a synapomorphy of the tribes Arabideae and Alysseae.
      Photographs by Liang-Min Liu, Xin-Yu Du, Cen Guo, and De-Zhu Li. Designed by Liang-Min Liu, Xin-Yu Du, Cen Guo, and De-Zhu Li.
    • Ivan Frolov, Jan Vondrák, Jiří Košnar, and Ulf Arup
      2021, 59 (3): 454–474
      Most lichens of the family Teloschistaceae (Ascomycota) produce yellow-orange-red anthraquinone pigments. However, the genus Pyrenodesmia encompasses species in which anthraquinones are absent and replaced by a gray pigment Sedifolia-gray. It was shown recently that these species are related to taxa with both anthraquinones and Sedifolia-gray (Caloplaca xerica group, C. haematites group, and C. cretensis) and to species with a brown pigment instead of both anthraquinones and Sedifolia-gray (C. demissa, C. obscurella, and C. reptans). Nevertheless, relationships between mentioned anthraquinone-containing and anthraquinone-lacking species remained unclear. In total, 8 DNA loci from 41 species were used here to resolve these uncertainties. We concluded that C. demissa, C. obscurella, and C. reptans are rather distant from the core of Pyrenodesmia, and we place them outside of Pyrenodesmia sensu lato. Within Pyrenodesmia sensu lato, three lineages were revealed and recognized on a generic level: the genus Pyrenodesmia sensu stricto (21 species), the genus Kuettlingeria (14 species), which is resurrected here, and the genus Sanguineodiscus (4 species), which is newly described here. The genus Pyrenodesmia includes taxa that never contain anthraquinones, but Sedifolia-gray. It matches with the former C. variabilis group. Taxa of the genera Kuettlingeria and Sanguineodiscus have anthraquinones in their apothecia and Sedifolia-gray in their thalli. The genus Kuettlingeria includes the former C. xerica group plus C. cretensis and C. diphyodes. The genus Sanguineodiscus includes the former C. haematites group and C. bicolor. The identity of Kuettlingeria (Caloplaca) diphyodes was clarified and the name Pyrenodesmia helygeoides was resurrected. Twenty-four new combinations were proposed.
    • Chao Xu and De‐Yuan Hong
      2021, 59 (3): 475–489
      Previous phylogenetic analyses found that the largest genus in the tribe Campanuleae, Campanula L. is polyphyletic. The genus is extremely intermingled, involving more than 50 genera, but no generic reappraisal has been attempted. For undertaking further phylogenetic analyses and subsequent generic reappraisal of the tribe, we sampled 333 samples, representing 27 of 28 genera currently recognized. Among them, 146 samples and two genera, Cylindrocarpa Regel and Sergia Fed., were newly sequenced. Six chloroplast DNA loci (atpB-rbcL, matK, petD-intron, rbcL, rpl16, and trnL-F) and internal transcribed spacer were used to undertake phylogenetic analyses. Our chloroplast DNA phylogeny comprises 24 clades, that is, 18 Cam clades and six genera, Feeria Buser, Homocodon D. Y. Hong, Jasione L., Peracarpa Hook. f. & Thomson, Trachelium L., and Favratia Feer. Campanula species are scattered among the 18 Cam clades and the six genera, and some of them join with well-established genera like Phyteuma L. and Adenophora Fisch. In the phylogeny Musschia Dumort. is at the basal position, but Jasione's position is unclear, whether in the tribe Campanuleae or in Wahlenbergieae; the other 22 lineages are grouped into two major clades: clade A comprising Cam 13–17 plus Feeria and Trachelium, and clade B comprising Cam 02, 03, 04-1, 04-2, and 06-12 plus Homocodon and Peracarpa. We found that the molecular phylogeny is closely correlated with morphology, particularly pollen morphology: clade A with pollen 3-porate and capsule dehiscent mostly by basal pores; and clade B with pollen mostly 4 (5–15)-porate and capsule dehiscent mostly by apical-middle pores. A generic reappraisal of the tribe is suggested based on the integrated phylogenetic analyses.
    • Ricarda Riina, Tamara Villaverde, Mario Rincón‐Barrado, Julià Molero, and Isabel Sanmartín
      2021, 59 (3): 490–503
      The sweet tabaiba (Euphorbia balsamifera Ait.) is one of the classical examples of the disjunct biogeographic pattern known as Rand Flora. This species is currently circumscribed to comprise two subspecies, Euphorbia balsamifera subsp. balsamifera and E. balsamifera subsp. adenensis (Deflers) P.R.O. Bally, with their respective areas of distribution separated by a gap of about 2000 km across Central-East Africa. We use multiple sources of evidence including phylogenomics, morphometrics, lineage ages, and climatic niche analysis to disentangle the confusing taxonomy around this charismatic Euphorbia lineage. Based on our integrative approach, we reestablish the two current subspecies to the rank of species (E. balsamifera Ait., E. adenensis Deflers) and resurrect the long forgotten E. sepium N.E. Br., a commonly used species in the western Sub-Saharan and Sahelian regions. The taxonomic treatment presented here includes an identification key, updated morphological descriptions, and lectotypification of several names.
    • This image shows a wild population of Euphorbia sepium in Western Sahara. We resurrected this long-hidden taxon using a multiple evidence approach, including phylogenomics, divergence times, morphology, distribution, and climatic preferences. Euphorbia sepium is sister to the other sweet tabaibas: E. balsamifera and E. adenensis (Photo: R. Riina, 2017).
    • Chao‐Nan Cai, Hui Ma, Xiu‐Qin Ci, John G. Conran, and Jie Li
      2021, 59 (3): 504–514
      The biologist's ruler for biodiversity is the species; accurate species identification is fundamental to the conservation of endangered species and in-depth biological scientific exploration. However, the delimitation and affinities of Horsfieldia in China has been controversial, owing in part to very low levels of molecular divergence within the family Myristicaceae. Because species boundaries and phylogenetic relationships within Horsfieldia are also unclear, 13 samples were collected across its distribution in China and their genomes were subjected to shotgun sequencing using Illumina platforms. A total of 40 487 994–84 801 416 pair-end clean reads were obtained and, after assembly, the complete chloroplast genome was recovered for all samples. Annotation analysis revealed a total of 112 genes, including 78 protein-coding genes, 30 transfer RNA, and 4 ribosomal RNA genes. Six variable loci (petN-psbM, trnH-psbA, ndhC-trnV, psbJ-psbL, ndhF, and rrn5-rrn23) were identified. Phylogenetic analyses strongly support the presence of four distinct species of Horsfieldia in China. In addition, samples that had been identified previously as Horsfieldia kingii (Hook. f.) Warb. were indistinguishable from those of H. prainii (King) Warb., suggesting that if H. kingii does occur in China, it was not collected in this study. Similarly, the chloroplast genome of one H. hainanensis Merr. sample from Guangxi province was identical to H. tetratepala C. Y. Wu, suggesting that the distribution range of H. hainanensis might be narrower than assumed previously. The phylogenetic relationships between the Chinese Horsfieldia species based on the whole chloroplast genomes was supported strongly, indicating the potential for using entire chloroplast genomes as super-barcodes for further resolution of the phylogeny of the genus Horsfieldia.
    • Le‐Ke Lyu, Dong‐Lei Wang, Long Li, Ying‐Ying Zhu, De‐Chun Jiang, Jian‐Quan Liu, and Xiao‐Ting Xu
      2021, 59 (3): 515–523
      Accurate species delimitation is fundamental to biodiversity conservation. The endangered spruce Picea brachytyla (Franch.) E. Pritz. was suggested to be polyphyletic based on a limited number of samples in previous studies. To evaluate polyphyly of P. brachytyla, we sampled 139 individuals from 16 populations across most of its distributional range, plus representatives of two related species, Picea likiangensis (Franch.) E. Pritz. and Picea wilsonii Mast. We sequenced 13 nuclear loci and three chloroplast and two mitochondrial loci for the following species delimitation. Phylogenetic analyses of nuclear loci grouped all individuals of P. brachytyla from Sichuan and Chongqing into one distinct lineage and those from Yunnan and Tibet (southern distribution) nested within the P. likiangensis species complex. Structure analyses confirmed this result. Networks of chloroplast DNA haplotypes similarly showed that P. brachytyla from the southern distribution nested within the P. likiangensis species complex, whereas haplotypes for the northern distribution comprised a separate and well-supported lineage. These results suggest that P. brachytyla from the southern distribution is a part of the P. likiangensis species complex and should be removed from P. brachytyla. Our study highlights the utility of population genetic evidence in delimitating endangered species and understanding the conservation status of such species.
    • Wei Han and Yu Jia
      2021, 59 (3): 524–540
      The Sematophyllaceae s.l. (Sematophyllaceae s.str. + Pylaisiadelphaceae) is one of the most diversified families of pleurocarpous mosses, distributed worldwide. The familial definition and subfamilial delimitation of the family have been controversial since their inception. Phylogenetic analyses were carried out using Bayesian inference, maximum likelihood, and maximum parsimony analyses. Our molecular phylogenetic analysis using five molecular markers (nad5, rbcL, rps4, trnL-F, and 26S) from mitochondrial, chloroplast, and nuclear genomes revealed the paraphyly of the Pylaisiadelphaceae and the monophyly of Sematophyllaceae s.l. Based on the molecular and morphological evidence, the Sematophyllaceae s.l. were further divided into six subfamilies, Taxithelioideae, Isopterygoideae, Pylaisiadelphoideae, Aptychelloideae, Platygyrioideae, and Sematophylloideae. The Taxithelioideae is established to accommodate Taxithelium, Taxitheliella, and Vernieri, the Isopterygoideae is established to accommodate Isopterygium and Yakushimabryum, the Pylaisiadelphoideae is newly circumscribed to accommodate Brotherella, Pylaisiadelpha, and Orientobryum, the Aptychelloideae is established to accommodate Aptychella, the Platygyrioideae is temporarily established to accommodate Clastobryella, Clastobryum, Gammiella, Platygyrium, and Trachyphyllum, the Sematophylloideae is resurrected to accommodate the Sematophyllaceae s.str., and Isocladiella, Isocladiellopsis, Mastopoma, Heterophyllium, Pseudotrismegistia, Trismegistia, and Wijkia are transferred to the subfamily. A new classification for the Sematophyllaceae s.l. is then proposed.
    • Jie Gao, Zhi‐Long Liu, Wei Zhao, Kyle W. Tomlinson, Shang‐Wen Xia, Qing‐Yin Zeng, Xiao‐Ru Wang, and Jin Chen
      2021, 59 (3): 541–556
      Understanding the effects of the demographic dynamics and environmental heterogeneity on the genomic variation of forest species is important, not only for uncovering the evolutionary history of the species, but also for predicting their ability to adapt to climate change. In this study, we combined a common garden experiment with range-wide population genomics analyses to infer the demographic history and characterize patterns of local adaptation in a subtropical oak species, Quercus acutissima (Carruthers). We scanned approximately 8% of the oak genome using a balanced representation of both genic and non-genic regions and identified a total of 55 361 single nucleotide polymorphisms (SNPs) in 167 trees. Genomic diversity analyses revealed an east–west split in the species distribution range. Coalescent-based model simulations inferred a late Pleistocene divergence in Q. acutissima between the east and west groups as well as subsequent preglaciation population expansion events. Consistent with observed genetic differentiation, morphological traits also showed east–west differentiation and the biomass allocation in seedlings was significantly associated with precipitation. Environment was found to have a significant and stronger impact on the non-neutral than the neutral SNPs, and also significantly associated with the phenotypic differentiation, suggesting that, apart from the geography, environment had played a role in determining non-neutral and phenotypic variation. Our approach, which combined a common garden experiment with landscape genomics data, validated the hypothesis of local adaptation of this long-lived oak tree of subtropical China. Our study joins the small number of studies that have combined genotypic and phenotypic data to detect patterns of local adaptation.
    • Gan‐Ju Xiang, You‐Hao Guo, and Chun‐Feng Yang
      2021, 59 (3): 557–566
      Floral orientation has been suggested to be a functional floral trait that can enhance reproductive fitness through adaptation to both biotic factors (e.g., pollination) and abiotic factors (e.g., temperature). However, whether those factors drive the diversification of floral orientation needs to be explored through multiple related species. Phylogenetic relationships in Lonicera were identified by incorporating the species’ floral orientation (upward vs. downward) and pollinator types. Furthermore, transitions in floral orientation were evaluated together with pollinator shift, and seven Lonicera species were used to detect the influence of floral orientation on pollination and reproductive success. The relationship between temperature and the angle of floral orientation was investigated. Floral orientation in Lonicera showed that most of the closely related species within the same node displayed a similar pattern of floral orientation, and pollinator shift can lead to transitions between upward and downward orientation. Additionally, the angle of floral orientation increased with flowering phenology from spring to summer, and changing floral orientation significantly decreased pollination and seed production. Moreover, the average daily temperature during flowering phenology was significantly correlated with the angle of floral orientation. Our results indicate that pollinator shift could be an important event, leading to the diversification of floral orientation. Results of field investigations inferred that floral orientation should be a functional floral trait adapted to flowering phenology. Downward-facing flowers might help decrease heat loss to adapt to cold conditions. This study disentangled the influences of historical events and local adaptation on the evolution of floral orientation.
    • Jing Liu, Jie Wu, Xia Yang, and Yin‐Zheng Wang
      2021, 59 (3): 567–580
      Floral zygomorphy is thought of as an essential adaptation to specific pollinators. The CYCLOIDEA (CYC)-like genes belonging to the plant-specific TCP transcription factor family are the key regulators of floral zygomorphy. Their expression differentiations bring about diverse forms of floral zygomorphy. However, the regulatory mechanism underlying their expression differentiation remains unknown. In this study, we selected Chirita pumila D. Don, a zygomorphic member of Gesneriaceae, as a model to address this question. Mutant analysis shows that the CYC gene in C. pumila (CpCYC) plays an important role in controlling floral zygomorphy. Further functional investigation of CpCYC intron and 5′ regulatory regions indicates that an 899 bp promoter region is a key determinant of the dorsal-specific expression of CpCYC. In this region, using electrophoretic mobility shift assay and transient expression system, we identified three kinds of cis-regulatory elements with putative binding factors, that is, auxin responsive element, WRKY binding site, LEAFY binding site, and an element with an unknown binding factor. We undertook functional analyses of the two putative LEAFY binding sites, and found that LEAFY could directly activate and regulate CpCYC for its dorsal-specific expression in patterning floral zygomorphy. This research would shed significant light on the regulatory and evolutionary pathways underlying the spatial-specific expression of CYC-like genes for the development of zygomorphic flowers.
    • Lu Wang, Xiao‐Ling Yan, Xiao‐Hui Zhang, and Yi Ren
      2021, 59 (3): 581–595
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      Menispermaceae is one of the core groups of Ranunculales. The single fertile ovule in each ovary in Menispermaceae varies greatly in integument number, micropyle formation, and integument lobe. However, data regarding ovule morphogenesis in the family are very limited. In this study, we document ovule development of selected species in the Menispermaceae using scanning electron microscopy and light microscopy. Ovule development in Menispermaceae shows the following characteristics. Two ovules are initiated in a young carpel, one of them degenerates gradually and the other develops into a fertile ovule in subsequent stages. Bitegmic in Sinomenium Diels. and Cocculus DC. and unitegmic in Stephania Lour. The formation of unitegmy is probably due to integumentary shifting. The annularly initiated inner integument is of dermal origin and has 2–3 cell layers in the family, but the semi-annularly initiated outer integument is of both dermal and subdermal origin. Both inner and outer integument are cup-shaped at maturity. The cup-shaped outer integument is formed due to the outer integument's extension to the concave (adaxial) side of the funiculus. The obturator is well developed and consists of 2–3 cell layers in Cocculus or 9–11 cell layers in Stephania. Ovule development of Menispermaceae suggests some common characteristics between Cocculus and Sinomenium, and derived unitegmy supports molecular data that indicate Stephania is one of the late-diverging lineages in the family. Integument lobations are present. The sterile ovule shows variations in the degeneration process. These results will provide evidence for exploring the evolution of ovules in Ranunculales.
    • Bartosz Łabiszak, Julia Zaborowska, Błażej Wójkiewicz, and Witold Wachowiak
      2021, 59 (3): 596–610
      With the current rate of biodiversity loss, conservation management practices require a comprehensive understanding of eco-evolutionary relationships, history, and genetic structure of species. Assessments of genetic diversity are crucial, especially in rare, endemic, or threatened forest tree species with small and isolated populations, such as peat bog pine (Pinus uliginosa N.). Here, we used a novel approach, combining genetic diversity assessment, ecological niche modeling, and population demography inference to explore the complex history of a few remnant populations of this endangered pine. To asses the relative influence of isolation and fragmentation on genetic diversity in the taxonomic context, the patterns of genetic variation found in P. uliginosa were contrasted with those observed in its close relatives with much bigger distribution ranges and larger populations (Pinus sylvestris, Pinus mugo, and Pinus uncinata). We found a similar level of genetic diversity across the species at nuclear loci but contrasting patterns of variability distribution at chloroplast markers. We detected the signatures of an ancient genetic bottleneck dated at around 26 400 years ago, indicating a drastic reduction in the population size of P. uligionosa during the Last Glacial Maximum. In addition, we found substantial differentiation between current populations as a result of enhanced genetic drift during long-lasting isolation. The research suggests potential conservation management strategies for peat bog pine and emphasizes the importance of using complementary approaches for their successful development.
    • Zack J. Quirk and Elizabeth J. Hermsen
      2021, 59 (3): 611–621
      A new fossil species of Corylopsis (Hamamelidaceae), C. grisea Quirk & Hermsen sp. nov, based on seeds from the early Pliocene Gray Fossil Site (GFS), eastern Tennessee, USA, is described. The assignment of the seeds to Hamamelidaceae, subfamily Hamamelidoideae, is based on the overall size of the seeds, smooth testa, lack of a seed wing, and the presence of a terminal hilar scar. The assignment to the genus Corylopsis is based on seed size as well as the presence of a hilar facet, in addition to the hilar scar. Although Corylopsis persists only in East Asia today, its fossil record indicates that the genus was widespread across the Northern Hemisphere in the past. Prior to its discovery at GFS, Corylopsis was only known from the Paleogene in North America. The presence of C. grisea at GFS extends the fossil record of Corylopsis in North America to the Neogene and reinforces the interpretation of GFS as a forested refugium that provided a relatively moist, equable environment where subtropical to warm temperate plants could persist during a time of cooling and drying in the continental interior of North America. Its presence provides additional evidence for the biogeographic connection between the GFS paleoflora and the modern flora of eastern Asia.
Editors-in-Chief
Song Ge
Jun Wen
Impact Factor
4.098
JCR 2020 IF ranking: 41/235 (Plant Sciences, top 17.24%, 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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