| 1. |
- Hedrén, Mikael, et al.
(author)
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Geographical variation and systematics of the tetraploid marsh orchid Dactylorhiza majalis subsp sphagnicola (Orchidaceae) and closely related taxa
- 2012
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In: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 1095-8339 .- 0024-4074. ; 168:2, s. 174-193
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Journal article (peer-reviewed)abstract
- Dactylorhiza majalis subsp. sphagnicola is an allotetraploid marsh orchid derived from parents closely similar to present-day D. incarnata and the western European form of D. maculata subsp. maculata, suggesting that it has a postglacial origin. It extends from northwestern continental Europe into areas formerly covered by the Weichselian ice sheet in mid-Scandinavia. Here, we studied the variation at both the plastid and nuclear marker systems to describe the geographical variation in subsp. sphagnicola and its evolutionary history. We investigated whether subsp. sphagnicola is affected by secondary hybridization and gene flow from its parental lineages or from other allotetraploid marsh orchids, and we also compared subsp. sphagnicola with other allotetraploids of similar origins. We analysed 492 plants from 50 populations. Thirty-seven populations were collected as potential Dactylorhiza majalis subsp. sphagnicola, five as subsp. sesquipedalis (D. elata), one as D. elata subsp. brennensis, one as subsp. calcifugiens, one as subsp. occidentalis and the remaining five as populations with some affinity to subsp. lapponica (including D. traunsteineri). All populations were analysed for plastid haplotypes and nuclear internal transcribed spacer (ITS) allele frequencies, and a subset of 43 populations was analysed for five nuclear microsatellite loci. Dactylorhiza majalis subsp. sphagnicola was dominated by a single plastid haplotype that was also dominant in western European D. maculata subsp. maculata, and most of the alternative haplotypes differed by only one mutation from the dominant one. There was more variation in nuclear microsatellites and ITS, and the variation was geographically structured in these markers. Subspecies occidentalis and calcifugiens shared haplotypes with subsp. sphagnicola, whereas subsp. sesquipedalis and brennensis had other haplotypes. Dactylorhiza majalis subsp. sphagnicola may have a postglacial origin within its present continental distribution. It has incorporated genetic material from D. maculata subsp. maculata by secondary hybridization and introgression, and some northern populations have assimilated strongly divergent haplotypes from the northeastern form of D. maculata subsp. maculata. Subspecies sphagnicola has also evolved morphologically divergent local populations in the north that do not differ from the typical populations in genetic markers. It may form mixed populations with other allotetraploid subspecies of D. majalis and, at least at one site, it has become integrated with subsp. lapponica, demonstrating that independently derived allotetraploids may contribute to a common gene pool. Subspecies calcifugiens seems to be derived from subsp. sphagnicola, and further studies based on a larger sample may confirm that it is better recognized as a variety. The so-called D. elata subsp. brennensis is of hybrid origin and combines markers from subsp. sesquipedalis with markers from the D. majalis core complex, possibly subsp. majalis. The new combination Dactylorhiza majalis subsp. sesquipedalis (Willd.) H.A.Pedersen & Hedren comb. nov. is provided. (C) 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 168, 174193.
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| 2. |
- Prentice, Honor C, et al.
(author)
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Mosaic variation in allozyme and plastid DNA markers in the European ranges of Silene vulgaris and its partially sympatric relative S-uniflora (Caryophyllaceae)
- 2011
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In: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 1095-8339 .- 0024-4074. ; 166:2, s. 127-148
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Journal article (peer-reviewed)abstract
- The perennial herbs Silene vulgaris and S. uniflora are closely related, partially sympatric and interfertile, yet morphologically distinct. We used nuclear (allozyme) and plastid (polymerase chain reaction-restriction fragment length polymorphism) DNA markers to investigate whether these species have a shared history of postglacial colonization and hybridization in Europe, as inferred from large-scale patterns of geographic variation. The majority of plastid haplotypes and allozyme alleles were widespread and patchily distributed within both species and there was no geographic structure in the distributions of shared allozymes or haplotypes. The mosaic variation is consistent with a scenario in which repeated episodes of interspecific hybridization pre-dated the largely allopatric range expansion of the two species during the postglacial period. Our overall results are not consistent with a scenario of extensive hybridization and introgression during the postglacial range expansion of the species or within their current areas of sympatry, but we found some evidence for local, postglacial evolution and hybridization in the Baltic region. (C) 2011 The Linnean Society of London, Botanical Journal of the Linnean Society, 2011, 166, 127-148.
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| 3. |
- Rydin, Catarina, et al.
(author)
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The female reproductive unit of Ephedra (Gnetales) : comparative morphology and evolutionary perspectives
- 2010
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In: Botanical journal of the Linnean Society. - : Wiley. - 0024-4074 .- 1095-8339. ; 163:4, s. 387-430
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Journal article (peer-reviewed)abstract
- Morphological variation in Ephedra (Gnetales) is limited and confusing from an evolutionary perspective, with parallelisms and intraspecific variation. However, recent analyses of molecular data provide a phylogenetic framework for investigations of morphological traits, albeit with few informative characters in the investigated gene regions. We document morphological, anatomical and histological variation patterns in the female reproductive unit and test the hypothesis that some Early Cretaceous fossils, which share synapomorphies with Ephedra, are members of the extant clade. Results indicate that some morphological features are evolutionarily informative although intraspecific variation is evident. Histology and anatomy of cone bracts and seed envelopes show clade-specific variation patterns. There is little evidence for an inclusion of the Cretaceous fossils in the extant clade. Rather, a hypothesized general pattern of reduction of the vasculature in the ephedran seed envelope, probably from four vascular bundles in the fossils, to ancestrally three in the living clade, and later to two, is consistent with phylogenetic and temporal analyses, which indicate that extant diversity evolved after the Cretaceous-Tertiary boundary. Notwithstanding striking similarities between living and Cretaceous Ephedra, available data indicate that the Mesozoic diversity went almost entirely extinct in the late Cretaceous causing a bottleneck effect in Ephedra, still reflected today by an extraordinarily low level of genetic and structural diversity.
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| 4. |
- Huang, Wei-Ping, et al.
(author)
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Molecular phylogenetics and biogeography of the eastern Asian-eastern North American disjunct Mitchella and its close relative Damnacanthus (Rubiaceae, Mitchelleae)
- 2013
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In: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 171:2, s. 395-412
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Research review (peer-reviewed)abstract
- Mitchella is a small genus of the Rubiaceae with only two species. It is the only herbaceous semishrub of the family showing a disjunct distribution in eastern Asia and eastern North America, extending to Central America. Its phylogeny and biogeographical diversification remain poorly understood. In this study, we conducted phylogenetic and biogeographical analyses for Mitchella and its close relative Damnacanthus based on sequences of the nuclear internal transcribed spacer (ITS) and four plastid markers (rbcL, atpB-rbcL, rps16 and trnL-F). Mitchella is monophyletic, consisting of an eastern Asian M. undulata clade and a New World M. repens clade. Our results also support Michella as the closest relative to the eastern Asian Damnacanthus. The divergence time between the two intercontinental disjunct Mitchella species was dated to 7.73 Mya, with a 95% highest posterior density (HPD) of 3.14-12.53 Mya, using the Bayesian relaxed clock estimation. Ancestral area reconstructions suggest that the genus originated in eastern Asia. The semishrub Mitchella appears to have arisen from its woody ancestor in eastern Asia and then migrated to North America via the Bering land bridge in the late Miocene.
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| 5. |
- Tschan, Georg F., et al.
(author)
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Trichome types, foliar indumentum and epicuticular wax in the Mediterranean gall oaks, Quercus subsection Galliferae (Fagaceae) : implications for taxonomy, ecology and evolution
- 2012
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In: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 169:4, s. 611-644
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Journal article (peer-reviewed)abstract
- Trichome characters are often considered to be taxonomically important in oak species. In this article, we investigate a group of Mediterranean oaks, Quercus subsection Galliferae and Q. pubescens, using a large dataset and covering the entire distribution range of the group. As a result of the different interpretations of terms in previous studies, trichome terminology was re-assessed aiming to obtain a practicable nomenclature. In contrast with previous studies, we found that acicular, bifurcate, fasciculate, stellate, uniseriate and capitate trichomes are represented in all taxa. One exception is the lack of bifurcate trichomes in Q. canariensis. This suggests that seemingly taxonomically informative presence/absence data for trichome types, as reported previously, may be the result of too small a sample size, and this may be unrepresentative. In combination with other morphological characters (leaf shape, size and texture), features of the indumentum, such as the floccose, easily removable trichomes in Q. canariensis, can be important in species delimitation. The use of trichome characteristics in Quercus subsection Galliferae requires exhaustive sampling of all taxa in order to extract a reproducible taxonomic signal from quantitative characters. This is the prerequisite for building datasets that can be used for phylogenetic analyses, investigations of character evolution and comparative morphological studies. (c) 2012 The Linnean Society of London, Botanical Journal of the Linnean Society, 2012, 169, 611644.
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| 6. |
- Bengtson, Annika, et al.
(author)
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Phylogeny and evolution of the South African genus Metalasia (Asteraceae-Gnaphalieae) inferred from molecular and morphological data
- 2014
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In: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 174:2, s. 173-198
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Journal article (peer-reviewed)abstract
- Metalasia is a genus in tribe Gnaphalieae (Asteraceae), endemic to South Africa and with its main distribution in the Cape Floristic Region. The genus comprises 57 species and, with a number of closely related genera, it constitutes the Metalasia clade'. A species-level phylogenetic analysis is presented, based on DNA sequences from two nuclear (internal and external transcribed spacer: ITS, ETS) and two plastid (psbA-trnH, trnL-trnF) regions together with morphological data. Analyses combining molecular and morphological data attempt not only to resolve species interrelationships, but also to detect patterns in character evolution. Phylogenetic analyses corroborate our earlier study and demonstrate that Metalasia is formed of two equally sized, well-supported sister groups, one of which is characterized by papillose cypselas. The results differ greatly from earlier hypotheses based on morphology alone, as few morphological characters support the phylogenetic patterns obtained. The two clades of Metalasia do, however, appear to differ in distribution, corresponding to the different rainfall regimes of South Africa. Analyses show a few taxa to be problematic; one example is the widely distributed M.densa which appears to be an intricate species complex.
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| 7. |
- Bisang, Irene, et al.
(author)
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Family affiliation, sex ratio and sporophyte frequency in unisexual mosses
- 2014
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In: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 174:2, s. 163-172
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Journal article (peer-reviewed)abstract
- Patterns of sex expression and sex ratios are key features of the life histories of organisms. Bryophytes are the only haploid-dominant land plants. In contrast with seed plants, more than half of bryophyte species are dioecious, with rare sexual expression and sporophyte formation and a commonly female-biased sex ratio. We asked whether variation in sex expression, sex ratio and sporophyte frequency in ten dioecious pleurocarpous wetland mosses of two different families was best explained by assuming that character states evolved: (1) in ancestors within the respective families or (2) at the species level as a response to recent habitat conditions. Lasso regression shrinkage identified relationships between family membership and sex ratio and sporophyte frequency, whereas environmental conditions were not correlated with any investigated reproductive trait. Sex ratio and sporophyte frequency were correlated with each other. Our results suggest that ancestry is more important than the current environment in explaining reproductive patterns at and above the species level in the studied wetland mosses, and that mechanisms controlling sex ratio and sporophyte frequency are phylogenetically conserved. Obviously, ancestry should be considered in the study of reproductive character state variation in plants.(c) 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2014, 174, 163-172.
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| 8. |
- Frajman, B., et al.
(author)
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Taxonomic revision of Atocion and Viscaria (Sileneae, Caryophyllaceae)
- 2013
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In: Botanical Journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 173:2, s. 194-210
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Journal article (peer-reviewed)abstract
- A species-level taxonomic revision of Atocion and Viscaria, based on a recent phylogenetic study, is presented. Atocion includes six species (A. armeria, A. compactum, A. lerchenfeldianum, A. reuterianum, A. rupestre and A. scythicinum), and Viscaria includes three species (V. alpina, V. asterias and V. vulgaris). The highest species diversity is found on the Balkan Peninsula. Species descriptions based on a study of morphological characters and generated using the Prometheus description model are provided and are also available in the Sileneae online database. Complete synonymy, notes on the ecology and geographical distribution of the taxa and an identification key are provided. Lectotypes for nine names (Lychnis helvetica, L. suecica, Silene armeria var. angustifolia, S. berdaui, S. lituanica, S. compacta, S. orientalis, S. reuteriana and Viscaria media) and a neotype for one name (S. lerchenfeldiana) are assigned. (C) 2013 The Linnean Society of London, Botanical Journal of the Linnean Society, 2013, 173, 194-210.
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| 9. |
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| 10. |
- Kainulainen, Kent, et al.
(author)
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Phylogenetic relationships and new tribal delimitations in subfamily Ixoroideae (Rubiaceae)
- 2013
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In: Botanical journal of the Linnean Society. - : Oxford University Press (OUP). - 0024-4074 .- 1095-8339. ; 173:3, s. 387-406
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Journal article (peer-reviewed)abstract
- Subfamily Ixoroideae is one of three major lineages in Rubiaceae, with approximately 4000 species. Previous molecular phylogenetic studies have indicated that many genera and tribes previously placed in other subfamilies are better considered as part of Ixoroideae. However, the internal resolution and clade support have generally been low, and several genera found to be nested in the subfamily do not appear to be associated with any described tribe. In order to resolve the phylogeny and assess the tribal delimitations in the expanded Ixoroideae, phylogenetic reconstructions were performed using Bayesian and parsimony analyses of six plastid DNA regions and a broad sampling of genera from all tribes of the subfamily. In the inferred phylogenetic hypotheses, the tribal relationships were mostly well supported, with Ixoroideae consisting of the Coffeeae and the Vanguerieae alliances as sister groups and a grade comprising Condamineeae, Henriquezieae, Posoquerieae, Retiniphylleae, Sipaneeae and the genus Steenisia. A revised tribal classification, including the description of five new tribes, Airospermeae, Augusteae, Scyphiphoreae, Steenisieae and Trailliaedoxeae, is provided.
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