Botanical Journal of the Linnean Society

Chau, John H.; O’Leary, Nataly; Sun, Wei-Bang; Olmstead, Richard G.

doi: 10.1093/botlinnean/box018pmid: N/A

AbstractBuddlejeae comprise c. 108 species in five commonly accepted genera: Buddleja, Chilianthus, Emorya, Gomphostigma and Nicodemia. Conflicting generic and infrageneric level classifications based on morphology attest to a need to evaluate relationships and trait evolution in a molecular phylogenetic framework. We use multiple independent loci from the nuclear and plastid genomes and representative taxonomic sampling to infer phylogenetic relationships using maximum likelihood and Bayesian analyses with single-locus and concatenated data and Bayesian multispecies coalescent analyses. Nicodemia and Gomphostigma are resolved as monophyletic. Chilianthus is not monophyletic, with three species in one clade and Buddleja glomerata (=Chilianthus lobulatus) possibly separate. Buddleja is paraphyletic with respect to Chilianthus, Emorya, Nicodemia and, probably, Gomphostigma. We propose a new classification to reflect phylogenetic relationships in Buddlejeae. Only Buddleja is retained at the generic level. Chilianthus, Nicodemia, Gomphostigma and Emorya are combined with Buddleja, with a new name and new combination erected for the two Emorya spp., Buddleja normaniae and B. rinconensis. Sectional classification of Buddleja is revised, with two new monotypic sections being proposed, Salviifoliae and Pulchellae, and Gomphostigma being lowered to sectional rank. Reproductive morphological traits traditionally used to define genera, including stamen exsertion, corolla shape and inflorescence type, were reconstructed on the phylogenetic tree and are inferred to have converged on similar states multiple times. Plesiomorphic trait states in Buddlejeae include capsular fruits, included stamens, white and tube-shaped corollas and paniculate inflorescences.

Zhou, Zhuo; Gu, Bo-Jian; Sun, Hang; Zhu, Hua; Tan, Yun-Hong

doi: 10.1093/botlinnean/box023pmid: N/A

AbstractA phylogenetic analysis based on 18S nuclear ribosomal DNA and four plastid markers (atpB, matK, rbcL and trnL-F) strongly supports the position of a new genus in Euphorbiaceae tribe Epiprineae (subfamily Acalyphoideae). Tsaiodendron dioicum gen. nov., sp. nov. is described and illustrated here as a new genus and species from Yunnan province, south-western China. The phylogenetic position of the new taxon is also supported by morphological and palynological evidence. Tsaiodendron is a distinct lineage sister to Cladogynos in tribe Epiprineae and is easily distinguished from related members of the tribe by the sexual system, inflorescence arrangement and presence of disc glands in the pistillate flower. Molecular divergence dating analysis based on matK, rbcL and trnL-F sequences suggests that Tsaiodendron originated in the late Miocene 10.42 Mya (95% HPD: 5.23–18.88 Mya). The origin of Tsaiodendron may be correlated with the Red River incision from south-western China. Tribe Epiprineae are shown to be monophyletic and phylogenetic relationships and evolutionary trends in the sexual system are also discussed based on our phylogenetic results.

Pirie, M. D.; Oliver, E. G. H.; Gehrke, B.; Heringer, L.; Mugrabi de Kuppler, A.; Le Maitre, N. C.; Bellstedt, D. U.

doi: 10.1093/botlinnean/box021pmid: N/A

AbstractAs one of the largest genera of flowering plants, the richness of species in Erica (Ericaceae) is all the more remarkable because > 80% of the > 800 species are endemic to the smallest floral kingdom, the Cape Floristic Region (CFR) of South Africa. In the CFR, pockets of narrowly endemic taxa appear in close juxtaposition with their widespread and variable relatives. The taxonomic challenges of Cape Erica are epitomized by the complex Cape ‘abietina/viscaria clade’, currently comprising at least 25 species. We reassess species boundaries and patterns of regional endemism in this clade using a phylogenetic tree inferred from multiple nuclear ribosomal and plastid DNA sequences. We show that the seven currently recognized subspecies of E. abietina represent at least three independent, morphologically distinct lineages with non-overlapping geographical distributions. We resurrect the name E. grandiflora to include E. abietina subsp. aurantiaca and subsp. perfoliosa and we provide a new name for E. abietina subsp. petraea (E. situshiemalis). This means that E. abietina is now an additional endemic species for the Cape Peninsula, including the natural World Heritage Site, Table Mountain National Park.

Hao, Guoqian; Al-Shehbaz, Ihsan A.; Ahani, Hamid; Liang, Qianlong; Mao, Kangshan; Wang, Qian; Liu, Jianquan

doi: 10.1093/botlinnean/box024pmid: N/A

AbstractIn this comprehensive study of Eutrema (Brassicaceae), five DNA markers [nuclear internal transcribed spacer (ITS) and plastid matK, rbcL, trnH-psbA and trnL-F] were sequenced for 183 individuals of 32 species of Eutrema s.l. and the closely related members of tribe Eutremeae, Chalcanthus and Pegaeophyton. The genetic-gap analyses showed that five previously described taxa are polyphyletic, and we identified 37 potential species units or independently evolving lineages. Further phylogenetic analyses were based on sequence variations of these five-marker barcodes for the typical representatives of all species units and they showed that the monospecific Chalcanthus, Pegaeophyton nepalense and P. scapiflorum are nested in and should be transferred to Eutrema, whereas P. watsonii was sister to Pycnoplinthopsis of tribe Euclidieae. Three clades were recovered in the expanded Eutrema based on the plastid DNA phylogenetic trees. However, phylogenetic relationships of some species in two later diverging clades are incongruent between ITS and plastid DNA trees and within them. These incongruences suggest possible hybridizations, incomplete lineage sorting or parallel evolution during recent species diversification in the genus. Furthermore, molecular dating and biogeographical analyses suggested that the recircumscribed Eutrema s.l. probably originated in eastern Asia, probably in central China. The origin and early divergence between three major clades of Eutrema, which are distributed mainly in central China, central Asia and the Qinghai–Tibetan Plateau (QTP), occurred in the Late Oligocene and Early Miocene, probably reflecting the extensive plateau uplifts and Asian aridification during that period. However, further diversification events from the Late Miocene to the Pleistocene, especially in response to the later QTP uplifts and climatic oscillations, might have promoted speciation of more current species through allopatric divergence and hybridization in that region. Several important taxonomic traits seem to have arisen multiple times with obvious parallel evolution. The new name E. baimashanicum and the new combinations E. nepalense, E. purii, E. renifolium, E. robustum, E. scapiflorum, E. xingshanensis and Aphragmus minutus are proposed. This case study highlights the importance of using DNA barcode sequences from multiple individuals or populations to solve evolutionary questions in a given genus.

Koch, Marcus A.; Grosser, Jan

doi: 10.1093/botlinnean/box020pmid: N/A

AbstractPhylogenetic relationships and the evolutionary history of East Asian Arabis spp. (Brassicaceae) were investigated using plastid trnL-F and nuclear internal transcribed spacer 1 and 2 sequences (ITS). This study tested the widespread assumption of the occurrence of Arabis hirsuta in East Asia and, in particular, in China. We were able to show that this is not the case. East Asian and North American Arabis are represented by three evolutionary lineages that arose via reticulate evolution among taxa, which are more closely related to A. planisiliqua subsp. nemorensis and A. ciliata. Early divergence of these three lineages is placed in the Pliocene, mostly probably in East Asia. In Arabideae, the A. planisiliqua subsp. nemorensis lineage probably served as one parental source; however, this species shows, at present, a wide Eurasian distribution, but it does not reach East Asia and the amphi-Beringian region. The second parental source was difficult to define, because respective sister species are no longer present in East Asia and all close relatives are distributed in Europe and Asia Minor only. In all three evolutionary lineages amphi-Beringian distribution and differentiation patterns date back to the Pleistocene. However, all three lineages have had secondary contact and additional reticulate evolutionary patterns among them are demonstrated.

Nuñez-Zapata, Jano; Alors, David; Cubas, Paloma; Divakar, Pradeep K.; Leavitt, Steven D.; Lumbsch, H. Thorsten; Crespo, Ana

doi: 10.1093/botlinnean/box022pmid: N/A

AbstractDisjunct intercontinental distributions have always fascinated biologists. With the increasing availability of molecular sequence data, there is a renewed interest in historical biogeography, especially in groups in which species boundaries have changed dramatically as a result, such as lichenized fungi. In the hyperdiverse family Parmeliaceae, Parmelina and Myelochroa have contrasting centres of distribution, with Myelochroa being most diverse in eastern Asia and Parmelina in Western Europe and the Mediterranean. We used multi-locus sequence data from 53 specimens to understand the impact of historical events on the current distribution patterns in these genera. We reconstructed phylogenetic relationships, estimated divergence times and inferred ancestral distributions. Our analyses suggested that the ancestor of the two genera occurred in the Old World and that these genera split during the Eocene. Diversification in both genera was estimated to have occurred during the Miocene, with the ancestor of Myelochroa probably occurring in Asia, whereas the ancestor of Parmelina probably occurred in the Turanian region and Europe or only Europe. The two Parmelina spp. occurring in the New World (P. coleae, P. yalungana) are not closely related and migrated independently from the Old World.

Herklotz, Veit; Mieder, Nadine; Ritz, Christiane M.

doi: 10.1093/botlinnean/box025pmid: N/A

AbstractPolyploid, hemisexual dogroses are known for their complicated reticulate evolutionary history and their ongoing hybridization events that challenge taxonomic concepts. We investigated how spontaneous hybrids between subsections Rubigineae and Caninae can be identified by cytological, genetic and morphological analyses and how they fit into the current taxonomic treatment. We sampled plants from mixed stands of both subsections in Germany and performed morphological measurements. We compared the morphological data with data from flow cytometry and microsatellite analyses compiled from a previous study based on a much wider sampling. Most of the investigated plants were pentaploid, but some species were composed of tetra- and hexaploid individuals co-occurring with the pentaploids. In Germany, all hexaploid plants were of hybridogenic origin and they were more frequently found in south-western Germany. Genetic and morphological data differentiated clearly between subsections and between informal aggregates of subsection Rubigineae. However, the currently accepted microspecies could be neither genetically nor morphologically unambiguously recognized. In contrast, multivariate analyses of genetic and morphological data distinguished between hexaploid and pentaploid cytotypes of the R. rubiginosa aggregate. The hexaploid hybridogenic individuals, mostly identified as R. micrantha, were characterized by more hairs and fewer glands on the leaflets and a smaller angle of the lamina base, characters typical for the paternal parent of subsection Caninae.

Neri, Jordana; Wendt, Tânia; Leles, Bruno; dos Santos, Manoel Francisco; Palma-Silva, Clarisse

doi: 10.1093/botlinnean/box026pmid: N/A

AbstractDivergence in reproductive systems among plant species often involves changes in floral traits. The distance separating stigmas and anthers (herkogamy) directly affects the relative importance of reproduction by outcrossing vs. selfing reproduction and can impact the integrity of sympatric species. We studied the reproductive biology of two closely related Vriesea spp. and investigated the variation in herkogamy among sympatric and allopatric populations and their implication in mating system variation and reproductive isolation between sympatric sister species. Both species are self-compatible, but differ in reproductive systems. Reduction in herkogamy drives a higher incidence of selfing for V. scalaris, whereas V. simplex relies predominantly on outcrossing events. Manual interspecific crosses produced F1 hybrids and confirmed natural hybridization previously observed between these two species. The closer anther–stigma positioning may be related to a higher capacity for autonomous selfing and might be one possible reproductive barrier facilitating sympatric species coexistence.

doi: 10.1093/botlinnean/box019pmid: N/A