Search

Abstract Background In the large angiosperm order Lamiales, a diverse array of highly specialized life strategies such as carnivory, parasitism, epiphytism, and desiccation tolerance occur, and some lineages possess drastically accelerated DNA substitutional rates or miniaturized genomes. However, understanding the evolution of these phenomena in the order, and clarifying borders of and relationships among lamialean families, has been hindered by largely unresolved trees in the past. Results Our analysis of the rapidly evolving trnK/matK, trnL-F and rps16 chloroplast regions enabled us to infer more precise phylogenetic hypotheses for the Lamiales. Relationships among the nine first-branching families in the Lamiales tree are now resolved with very strong support. Subsequent to Plocospermataceae, a clade consisting of Carlemanniaceae plus Oleaceae branches, followed by Tetrachondraceae and a newly inferred clade composed of Gesneriaceae plus Calceolariaceae, which is also supported by morphological characters. Plantaginaceae (incl. Gratioleae) and Scrophulariaceae are well separated in the backbone grade; Lamiaceae and Verbenaceae appear in distant clades, while the recently described Linderniaceae are confirmed to be monophyletic and in an isolated position. Conclusions Confidence about deep nodes of the Lamiales tree is an important step towards understanding the evolutionary diversification of a major clade of flowering plants. The degree of resolution obtained here now provides a first opportunity to discuss the evolution of morphological and biochemical traits in Lamiales. The multiple independent evolution of the carnivorous syndrome, once in Lentibulariaceae and a second time in Byblidaceae, is strongly supported by all analyses and topological tests. The evolution of selected morphological characters such as flower symmetry is discussed. The addition of further sequence data from introns and spacers holds promise to eventually obtain a fully resolved plastid tree of Lamiales.

The genus Gomphrena comprises about 120 species in the Americas and 35 in Australia. Previous research revealed that Gossypianthus, Lithophila and Philoxerus are closely related but the monophyly of Gomphrena remained unresolved. Our aim was to clarify phylogenetic relationships in Gomphrena and allies based on a thorough sampling of species and to reconstruct the evolution of morphological characters including C4 photosynthesis, and to explore the disjunction of the Australian taxa. We generated datasets of plastid (matK-trnK, trnL-F, rpl16) and nrITS representing 45 taxa of Gomphrena plus relatives and analysed them with parsimony, likelihood and Bayesian methods. Ancestral states of phenotypic characters were reconstructed with BayesTraits. BEAST was employed for divergence time estimates using an extended Amaranthaceae–Chenopodiaceae dataset to place fossil calibration points. Gossypianthus is closely related to a Gomphrena radiata–G. umbellata–G. tomentosa clade and G. meyeniana, whereas Lithophila and Philoxerus appear as successive sisters of the Australian species of Gomphrena. The majority of Andean species appears in a large clade including annual and perennial species. The Cerrado species Gomphrena mollis and G. rupestris, which are C3, constitute an early-branching lineage, whereas the core Gomphrena clade is C4 and has the inner two sepals strongly compressed as synapomorphy. A major subclade evolved inflorescences with subglobose paracladia in a whorl, supported by pseudanthial leaves. Whereas the core Gomphrena clade started to diversify around 11.4 Ma (8.45–14.5 95% highest posterior density [HPD]) the Australian lineage split at only 4.8 Ma (2.61–7.18 HPD). Our detailed phylogenetic analysis of Gomphrena depicts 10 major lineages including segregate genera. We hypothesize that an adaptation to costal habitats was followed by long-distance dispersal to Australia. We also propose a revised genus concept of Gomphrena including Gossypianthus, Lithophila and Philoxerus, considering that these small segregate genera were based on states of vegetative characters exhibiting adaptations to specific habitats rather than phylogeny and overall morphology. Citation: Ortuño Limarino T. & Borsch Th. 2020: Gomphrena (Amaranthaceae, Gomphrenoideae) diversified as a C4 lineage in the New World tropics with specializations in floral and inflorescence morphology, and an escape to Australia. – Willdenowia 50: 345–381. doi: https://doi.org/10.3372/wi.50.50301 Version of record first published online on 31 August 2020 ahead of inclusion in December 2020 issue. [ABSTRACT FROM AUTHOR]

Premise of research. The Caribbean is an important area of species diversity within the large pantropical genus Phyllanthus. With the goal of illuminating the evolutionary origins of Caribbean Phyllanthus , we undertook a phylogenetic analysis significantly increasing previous samplings of the genus in the Neotropics. We reconstructed the evolution of selected morphological characters and evaluated the implications of our results in light of the representation of Caribbean and Neotropical species in the infrageneric classification of the genus. Methodology. We estimated phylogentic trees using parsimony, Bayesian, and likelihood approaches based on plastid and nuclear sequence data sets. These represented 78 taxa from the Neotropics, most of which were generated for this study, as well as most other subgenera and sections of Phyllanthus and other genera of Phyllanthaceae. Four vegetative and four floral morphological characters were assessed for the whole study group. Ancestral character states were reconstructed using BayesTraits. Pivotal results. Plastid and nuclear partitions agree on a highly supported Caribbean clade that contains the vast majority of the species from this region as being part of a large Neotropical clade. Another small Caribbean clade is found nested among African linages. Although morphological characters exhibit some level of homoplasy, some trends are evident, for example, in the large Neotropical clade. Conclusions. The majority of species in the Caribbean belong to a single clade that has evolved from Neotropical ancestors. This is well circumscribed with morphology and corresponds to subgenus Xylophylla , the concept of which is adjusted here to be monophyletic. The existence of a small Caribbean clade related to African species marks a noteworthy case of Caribbean plant origin. Although phyllanthoid branching is not a synapomorphy for Phyllanthus s.l. (including Breynia , Glochidion , and Sauropus), combinations of vegetative and floral characters allow a clear assignment to the Phyllanthus s.l. clade. [ABSTRACT FROM AUTHOR]

Aristolochiaceae comprises some 600 species occurring worldwide with concentration in tropical and subtropical regions. The family belongs to a basal angiosperms clade concisting of Piperaceae, Saururaceae, and Lactoridaceae; the latter is either nested in or sister to Aristolochiaceae. Although Aristolochiaceae is generally split into subfamilies Asaroideae and Aristolochioideae, strong disagreement exists in systematic relationships at the generic level. This is particularly true for Pararistolochia and Isotrema, although they can be recognized by several morphological synapomorphies. We present a phylogeny based on trnT-trnF for Aristolochiaceae. The two subfamilies are well supported with Saruma and Asarum being sistergroups. Pararistolochia and Isotrema form well supported monophyletic clades, with Endodeca sensu Huber beeing closlely related to Isotrema. The morphologically unique, monotypic Holostylis nests within the South American species of 'Howardia' sensu Huber. Based on a broad sampling of outgroup taxa (e.g., Saururaceae, Piperaceae, Austrobaileaceae, Amborellaceae) we also allows to look for close relatives of the Aristolochiaceae. Special attention was paid to the problem of an presently unresolved position of Lactoris fernandeziana. The outgroup results of this study show Piperaceae and Saururaceae forming a monophyletic group with Lactoris at its base and confirming this grade being sister to Aristolochiaceae.

The carnivorous angiosperm family Lentibulariaceae comprises about 280 species in 3 genera (Utricularia, Pinguicula, Genlisea) and is of nearly worldwide distribution. It belongs to the order Lamiales within euasterids. From representatives of Lentibulariaceae and different outgroup taxa of the Lamiales the whole trnK intron including the matK gene was sequenced. The size of the matK coding region in Lentibulariaceae ranges between 1521 and 1581 bp. Size differences are caused by indels from 3 - 36 bp, which accumulate in the first half of the gene. The length of the noncoding region adjacent to the 5' end of matK is 729 - 780 bp, and of the region adjacent to the 3' end 305 - 330 bp. Sequence variability within Lentibulariaceae is 23% for the coding region as compared to 27% for the noncoding region. For the large 5' noncoding region a robust alignment was obtained, whereas the short 3' region could not be aligned all over due to high numbers of indels. Parsimony analyses based on substitutions and carried out independently for the matK gene and the long 5' noncoding region yielded identical, well resolved phylogenies with high bootstrap and decay support. The matK indels appear to be highly informative phylogenetically and seem to be much less homoplastic than substitutions. Lentibulariaceae appear monophyletic and Byblis is resolved as closest relative. Within Lentibulariaceae, Pinguicula diverges first and its species appear as a terminal clade on a long branch. Genlisea is sister to Utricularia with quite similar branch-lengths within the topology of the Genlisea-Utricularia-clade.

We analyzed DNA sequences of the plastid gene matK to infer phylogenetic relationships among angiosperms. Our sample includes seven monocot families (Anthericaceae, Asparagaceae, Convallariaceae, Joinvilleaceae, Poaceae, Restionaceae, and Trilliaceae) and 19 dicot families (Amborellaceae, Anthospermataceae, Brassicaceae, Calycanthaceae, Ericaceae, Fabaceae, Hamamelidaceae, Hernandiaceae, Illiciaceae, Lauraceae, Loganiaceae, Magnoliaceae, Monimiaceae, Nymphaeaceae, Paeoniaceae, Rosaceae, Rubiaceae, Saxifragaceae, and Scrophulariaceae). The tree is rooted with three families of conifers (Pinaceae, Cupressaceae, and Taxaceae) plus Gnetum (Gnetaceae). Including all species (AmboreIla and lllicium are missing the 5' one-third of the gene), the angiosperms are strongly supported as monophyletic. The base is a polytomy of six lineages: Amborella, Illicium, monocots, Nymphaeales, magnoliids, and tricolpates. Magnoliaceae are sister to all other members of the Magnoliid complex sampled. Saxifragales species form a clade with the rosids that is sister to the asterid clade. When Amborella and Illicium are excluded from the analysis, a single most parsimonious tree is recovered with a CI of 0.47 and an RI of 0.70 excluding uninformative characters. This tree shows Nymphaeales (bootstrap of 100%) as sister to the other angiosperms; the latter are divided into two large clades with the magnoliids (99%) sister to the tricolpates (97%). Additionally, the Nymphaeales are supported by a 12-bp insertion, the monocots by a different 12-bp insertion, and the tricolpates by a 9-bp deletion.

A highly resolved phylogeny of basal angiosperms was inferred from sequences of the trnT-L- and trnL-F-spacers and the trnL-intron. A robust alignment was obtained, although it was complicated by the recognition of a large number of indels, mostly simple direct repeats ranging from 3-10 bp. About 30% of the aligned positions had to be excluded from analysis because of too high variability. Conifers and Ginkgo were used as outgroups. Gnetum shows such a high sequence divergence that no part of the trnT-F-region could be aligned with conifers, Ginkgo, or angiosperms. The ingroup comprises 35 taxa to represent all major lineages of basal angiosperms. In parsimony analysis, Amborella appears as sister to all other angiosperms examined. A Nymphaeales-clade (Nymphaeaceae plus Cabombaceae) and an Austrobaileya-Illicium-Schisandra-clade diverge next. These results are in agreement with recent phylogenies based on multiple coding regions. Bootstrap and decay support for the majority of nodes in the trees of the trnT-trnF-analysis was found to be high, and phylogenies obtained from separate versus combined analyses of the two spacers and the intron were largely congruent. Patterns of molecular evolution in the trnT-F-region are analyzed in order to elucidate these unexpected findings.

* Background and Aims Many African genera of the Amaranthaceae exhibit unique inflorescences that include sterile flowers modified to hooks or spines. Considering that the abundance of large terrestrial herbivores increased on the African continent with the expansion of grassland and savannah ecosystems, modified sterile flowers could have been an innovation that boosted the diversification of an African achyranthoid clade of Amaranthaceae, with large animals serving dispersal. * Methods We generated an extensively sampled phylogeny comprising 26 of the 31 achyranthoid genera as well as representatives of all other lineages of Amaranthaceae. Phylogenetic tree inference employed four genomic regions, using parsimony, likelihood and Bayesian inference methods. We estimated divergence times, evaluated trait-dependant changes and species diversification rates using state-dependent speciation and extinction models, and reconstructed ancestral character states for modified sterile flowers. * Key Results The achyranthoids were found to be a major clade of the Amaranthaceae, comprising mostly African members. Phylogenetic relationships within this clade were well resolved and supported two main subclades. Several genera were found to be polyphyletic. Our results indicate that the achyranthoids started to diversify ~28 million years ago, and that modified sterile flowers evolved multiple times. An asymmetry in transition rates towards the gain of sterile flowers was observed, whereas no trait-dependent increase in species diversification rates was detected. Bayesian rate heterogeneity analyses indicated that the achyranthoids diversified without significant rate shifts. * Conclusions The accumulation of modified sterile flowers within achyranthoids appears to result from the higher transition rates in favour of modified sterile flowers. Multiple gains suggest an adaptive value for this trait. However, epizoochory does not appear to fuel species diversification, possibly due to extensive gene flow through regularly migrating mammals, which limits the possibility of speciation by isolation. [ABSTRACT FROM AUTHOR]

Plant diversity is decreasing mainly through anthropogenic factors like habitat fragmentation, which lead to spatial separation of remaining populations and thereby affect genetic diversity and structure within species. Twenty populations of the threatened grassland species Crepis mollis were studied across Germany (578 individual plants) based on microsatellite genotyping. Genetic diversity was significantly higher in populations from the Alpine region than from the Central Uplands. Furthermore, genetic diversity was significantly positively correlated with population size. Despite smaller populations in the Uplands there were no signs of inbreeding. Genetic differentiation between populations was moderate (FST = 0.09) and no isolation by distance was found. In contrast, large-scale spatial genetic structure showed a significant decrease of individual pairwise relatedness, which was higher than in random pairs up to 50 km. Bayesian analyses detected three genetic clusters consistent with two regions in the Uplands and an admixture group in the Alpine region. Despite the obvious spatial isolation of the currently known populations, the absence of significant isolation by distance combined together with moderate population differentiation indicates that drift rather than inter-population gene flow drives differentiation. The absence of inbreeding suggests that pollination is still effective, while seed dispersal by wind is likely to be impaired by discontinuous habitats. Our results underline the need for maintaining or improving habitat quality as the most important short term measure for C. mollis. For maintaining long-term viability, establishing stepping stone habitats or, where this is not possible, assisted gene flow needs to be considered. [ABSTRACT FROM AUTHOR]

Abstract: With approximately 25 endemic species, the genus Pyrus (pears) is highly diverse in the Caucasus ecoregion. The majority of Caucasian pears inhabit xerophytic open woodlands or similar habitats, to which they display morphological adaptations, such as narrow leaves. The other species, both Caucasian and non‐Caucasian taxa, mainly inhabit mesophytic forests and display broad leaves. Using a representative taxon sampling of Pyrus from the Caucasus, Europe and Asia, we reconstruct phylogenetic relationships in the genus based on multiple plastid regions. We also estimate the divergence times of major clades in Pyrus, reconstruct the evolution of leaf shapes, and discuss the emergence of xeromorphic leaf traits. Our results confirm the monophyly of Pyrus and the existence of two major clades: (a) an E Asian clade with a crown group age of 15.7 (24.02–8.37 95% HPD) My, and (b) a W Eurasian clade that comprises species from Europe, SW Asia and the Caucasus and that displays a slightly younger crown group of 12.38 (19.02–6.41 95% HPD) My. The existing infrageneric classification of Pyrus was found partially incongruent with the inferred phylogenetic trees. Several currently accepted species were not recovered as monophyletic, indicating that current species limits require re‐evaluation. Ancestral character state reconstructions revealed several independent transitions from broad‐ to narrow‐shaped leaves in Pyrus, probably via intermediate‐shaped leaves. [ABSTRACT FROM AUTHOR]

We aimed to (i) assess the extant genetic diversity of the riparian relict treePterocarya fraxinifoliaacross its current distribution range in the South Caucasus, including the past refugial areas Colchis and Hyrcan, and (ii) test if a separation of these areas is reflected in its phylogeographic history. Genetic diversity of natural populations was examined using nuclear microsatellite and plastid DNA markers. Spatial genetic structure was evaluated using Bayesian clustering methods and the reconstruction of plastid DNA networks. Divergence times of Colchic and Hyrcanian populations were estimated via divergence dating using a relaxed molecular clock. Allelic richness, private allelic richness, and expected heterozygosity were significantly higher in Hyrcan than in Colchis and the Greater Caucasus, and significant genetic differentiation was revealed between the two groups. Whereas only two plastid haplotypes were detected for the Colchic and Caucasian populations, the Hyrcanian populations displayed 11 different haplotypes. Significant isolation by distance was detected in Hyrcan. The most recent common ancestor of allP. fraxinifoliahaplotypes was dated to a time well before a suggested glaciation period in the Caucasus during the late Pliocene (5.98 Ma [11.3–2.48 Ma HPD]). The widespread Colchic haplotype that also occurs along the southern slope of the Greater Caucasus and reaches south-eastern Azerbaijan has appeared more recently (0.24 Ma [1.41–0 Ma HPD]). This diversification pattern of Colchic haplotypes from ancient Hyrcanian haplotypes suggests a colonization of the region from south-east to north-west that predates the last glacial maximum (LGM). Natural populations ofP. fraxinifoliashow low-to-intermediate levels of genetic diversity and a significant decrease of diversity from Hyrcan to Colchis. However, the genetic differentiation between Colchic-Caucasian and Hyrcanian populations for nuclear markers suggests that independent gene pools existed in both areas at least since the LGM. Particular attention to conservation seems justified for the more diverse Hyrcanian populations. [ABSTRACT FROM AUTHOR]

Limonium (Plumbaginaceae) is a nearly cosmopolitan halophytic genus with ca. 350 species, a large number of which occurs in the Mediterranean region. We have generated a sequence dataset of several plastid (trnK intron including the matK gene, petD intron with the petB-petD spacer, trnL intron with the trnL-trnF spacer) and one nuclear region (nrITS), spanning the major lineages within the genus (102 accessions representing 76 species of Limonium) and related genera. Bayesian inference, maximum likelihood and maximum parsimony analyses converge on a Limonium clade that includes the genera Afrolimon, Eremolimon and Linczevskia. Plastid and nuclear trees congruently depict a number of major clades, most of them with a characteristic vegetative morphology and growing in specific habitats. Although the position of Afrolimon is incongruently resolved as the sister of a subclade comprising Limonium vulgare and relatives in the plastid trees versus being the sister to a Limonium sogdianum--L. bellidifolium--L. aureum clade in the nrITS tree, both genomic compartments show that Afrolimon is deeply nested in Limonium. Eremolimon is resolved as a close relative of L. sogdianum and L. ferganense based on plastid and nuclear genomic compartments. Our phylogenetic analysis resulted in an improved picture of internal relationships. Apart from the monophyletic subgenera Limonium subg. Limonium and L. subg. Pteroclados, nine wellsupported clades of L. subg. Limonium are evident, several of which are predominantly constituted by species of a certain geographic range. A subclade of IranoTuranian species (L. iranicum, L. suffruticosum and relatives) is shown to be unrelated to a L. axillare subclade, indicating an independent origin of the woody habit in these two lineages. Limonium sect. Iranolimon sect. nov. is described for the IranoTuranian woody lineage. The new combination L. sect. Circinaria comb. nov., is established for taxa sometimes included in Afrolimon. [ABSTRACT FROM AUTHOR]