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Many dung mosses (Splachnaceae) are characterized by insect-mediated spore dispersal. All of the entomophilous species are coprophilous, whereas anemophilous species are humicolous or epiphytic. The three species of the Voitioideae are coprophilous but are distinguished from other members of the family by sporangia that remain closed (cleistocarpous) and lack a peristome. Spores are released when the sporangial wall disintegrates. Phylogenetic analyses of nucleotide sequences of the trnL-trnF region and the rps4 locus (cpDNA) for 25 species of Splachnaceae suggest that this combination of characters arose twice within the Splachnaceae and that Voitia grandis is more closely related to species of Tayloria subgenus Tayloria rather to the other species of Voitia, which are nested within the genus Tetraplodon. Hence the new combination Tayloria grandis (Long) Goffinet & Shaw is made. Although the optimal trees were left unrooted, our results resolve the Voitioideae (i.e., the genus Voitia) as nested within the Splachnoideae. The phylogenetic significance of sporophytic characters within the family Splachnaceae is briefly discussed.
In this paper, molecular phylogenetic analyses were used to investigate a putative hybrid origin for Dendrochilum acuiferum, a species endemic to Mount Kinabalu, Sabah, Malaysia. Phylogenetic analyses of the plastid (pt) accD-psaI intergenic spacer region and a unique shared 117 bp indel indicate that D. grandiflorum and D. acuiferum are closely related. Direct sequencing of PCR products from the ITS 1 and 2 of the nuclear ribosomal repeat region revealed single site nucleotide polymorphisms in D. acuiferum that were additive between two hypothesized parents in addition to other sampled species. Dendrochilum acuiferum within-individual cloned ITS allelic sequence variants were analyzed in a phylogenetic context to determine the relative support for a hybrid (biphyletic) origin versus a nonhybrid (monophyletic) origin of the alleles. Because there was a significantly higher level of support for a hybrid origin of the alleles (P < 0.05), we subsequently compared likelihood scores for multiple parent pairs that could have hybridized. Although ptDNA evidence suggests Dendrochilum grandiflorum was the most likely maternal parent of D. acuiferum, ITS results are ambiguous about paternity because the phylogenetic results support D. grandiflorumD. stachyodes and D. grandiflorumD. kamborangense as equally likely parents of D. acuiferum. In addition, two other parent pairs could not be rejected (P > 0.05).
The minute, reduced plants of family Lemnaceae have presented a formidable challenge to systematic investigations. The simplified morphology of duckweeds has made it particularly difficult to reconcile their interspecific relationships. A comprehensive phylogenetic analysis of all currently recognized species of Lemnaceae has been carried out using more than 4,700 characters that include data from morphology and anatomy, flavonoids, allozymes, and DNA sequences from chloroplast genes (rbcL, matK) and introns (trnK, rpl16). All data are reasonably congruent (I(MF) < 6%) and contributed to strong nodal support in combined analyses. Our combined data yield a single, well-resolved, maximum parsimony tree with 30/36 nodes (83%) supported by bootstrap values that exceed 90%. Subfamily Wolffioideae is a monophyletic clade with 100% bootstrap support; however, subfamily Lemnoideae represents a paraphyletic grade comprising Landoltia, Lemna, and Spirodela. Combined data analysis confirms the monophyly of Landoltia, Lemna, Spirodela, Wolffia, and Wolffiella. Phylogenetic relationships are used to evaluate and refine the classification of duckweeds.
This work presents a reconstruction of the phylogenetic relationships between ten lineages of fescues based on the analysis of nuclear rDNA ITS sequences. Thirty two representatives of most native Western Mediterranean subgenera and sections of Festuca s.l. have been included in this survey in order to establish the evolutionary links between known groups of fescues (subg. Schedonorus, subg. Festuca sect. Festuca and sect. Aulaxyper) and other related Festuca groups that have been poorly studied or that are analyzed here for the first time (subg. Drymanthele, subg. Festuca sect. Subbulbosae, sect. Eskia, sect. Pseudatropis, sect. Scariosae, sect. Pseudoscariosa). Phylogenetic analysis identified two different clades, the “broad-leaved” Festuca and the “fine-leaved” Festuca, using Dactylis, Poa, Deschampsia, Secale, and Brachypodium as outgroups. The “broad-leaved” Festuca clade shows the consecutive sister divergence of the groups: i) the Subbulbosae pro parte clade (some Festuca paniculata s.l. taxa); ii) the Hesperochloa clade (Festuca kingii); iii) the “mixed” clade (incl. sect. Subbulbosae p.p., subg. Drymanthele, sect. Scariosae, and sect. Pseudoscariosa); and iv) the Schedonorus/Lolium clade, subdivided into the “Maghrebian” subclade and the “European Lolium” subclade. The “fine-leaved” Festuca clade is formed by a paraphyletic assemblage of sectional groups, where sects. Eskia and Pseudatropis are basal to sects. Festuca-AulaxyperVulpia. The closer affinities of Lolium to the European Schedonorus and of Vulpia to Festuca sect. Aulaxyper (”Festuca rubra complex”), stated by previous authors, is confirmed in our analysis. A new nomenclatural combination is proposed (Festuca arundinacea Schreb. subsp. arundinacea var. letourneuxiana (St.-Yves) Torrecilla et Catalán comb. nov.).
Digitaria killeenii A. S. Vega et Rúgolo, a new species from Bolivia, is described and illustrated. Additional micromorphological characters in the spikelets are also described. The presence of an apical, abaxial pair of stomata on the upper lemma and the presence of occasional brownish hairs on the lower palea constitute the first report in the genus Digitaria. The taxonomic position of D. killeenii is discussed and its inclusion in section Clavipilae (Stapf) Henrard is proposed. A comparative table and some remarks about the related taxa are included.
Parsimony analysis of plastid rpl16 sequences from 62 members of Tribe Cacteae, and four outgroup taxa yielded 1296 equally parsimonious trees of length 666. Strict consensus evaluation of these trees established a highly pectinate topology, which delimited clades within the tribe that correspond to several previously considered generic groups. Aztekium and Geohintonia, which manifest ribs in their stem morphology were shown to represent an early divergence in the tribe, forming a sister group to remaining members of the tribe. Clades containing other genera having ribbed stems also are basal to those that develop tubercles. The most derived clade forms a distinct group of typically small stemmed species with tubercular stem morphology. Within Mammillaria, species formerly placed in the genus Cochemiea and members of the Series Ancistracanthae formed a well-supported, sister clade to the remaining members of Mammillaria. Length variation of the intron in two members of Mammillaria series Stylothelae was also observed.
The Macaronesian clade of Crassulaceae comprises four genera (Aichryson, Aeonium, Greenovia, and Monanthes) that are largely endemic to Macaronesia, a region encompassing the Azores, Madeira, and the Cape Verde, Canary, and Salvage Islands. The monophyly of this clade has been supported by recent family-level phylogenetic analyses; however, the relationships within the clade remain uncertain. To resolve relationships within the Macaronesian clade, we sequenced several chloroplast DNA regions (matK and the trnL-trnF and psbA-trnH spacer regions) and the nuclear rDNA ITS region. Parsimony analyses of separate ITS and cpDNA data sets recover three major clades, corresponding to Aichryson, the perennial species of Monanthes, and Aeonium (including Greenovia). Congruence tests revealed significant heterogeneity between the ITS and cpDNA data sets. Comparison of the topologies resulting from analyses of these separate data sets indicated five instances of incongruence between the ITS and cpDNA that may be the result of cpDNA capture events. Those five cpDNA sequences that appear to be the result of hybridization were removed, and a combined cpDNA/ITS data set was constructed and analyzed. Parsimony analyses of this combined data set again resolve three major clades that correspond to Aichryson, Monanthes, and Aeonium (including Greenovia); however, the combined analyses provide greater resolution and higher internal support than the analyses of the separate data sets. Given this estimate of phylogeny, the Macaronesian clade most likely evolved from herbaceous, continental ancestors; the woody habit evolved once in Aichryson tortuosum and again in the ancestor of the Aeonium clade. Combined analyses of cpDNA and ITS for a large sampling of the Macaronesian Crassulaceae also confirms recent conclusions that Aeonium originated in Macaronesia and not in Africa and that the east African species, A. leucoblepharum, is of recent origin and represents long-distance dispersal from Macaronesia to Africa.
The phylogeny of Cercis (Fabaceae) was estimated with DNA sequences of the nuclear ribosomal ITS region and the 3′ end of the chloroplast gene ndhF. The combined analysis recovers three trees in which a well supported clade of North American and western Eurasian species is nested within a paraphyletic group of Chinese species. In the single most unambiguously resolved topology from these trees, C. canadensis from eastern North America is more closely related to C. siliquastrum from western Eurasia than to C. occidentalis from western North America. DIVA and character optimizations based on this topology suggest that the initial intercontinental divergence events in Cercis involved mesophytic ancestors. Subsequent inferred intercontinental divergence events involving xerophytic ancestors are consistent with the Madrean-Tethyan hypothesis, which postulates an early Tertiary floristic link between the arid regions of western North America and western Eurasia. Calibration of branch lengths with the fossil record suggests that the North American and western Eurasian lineages diverged between 6 and 32 million years ago. The oldest of these values is consistent with both the Madrean-Tethyan hypothesis (>23 million years ago) and dispersion across a North Atlantic land bridge connecting Europe to North America (>13 million years ago), whereas the youngest requires an explanation involving long-distance dispersal.
This is a molecular phylogenetic study of the group formerly known as Dryadeae, based on DNA sequences from the internal transcribed spacers, ITS, of nuclear ribosomal DNA and the trnL intron and the trnL-trnF intergenic spacer of the chloroplast. A total of 1.9 kb, for 26 ingroup species, were analyzed using parsimony and model-based Bayesian inference. Some clades are well supported by both data sets: the ingroup, with Fallugia as the sister to the rest of the clade; Sieversia in a strict sense; a clade consisting of all the herbaceous perennials, and some clades within this last group. Other clades, within the group of herbaceous perennials, differ between the analyses. The data sets in the present study do not support any previous circumscriptions of Geum nor any of the suggested segregate genera, except for the southern hemisphere Oncostylus. Morphological characters, notably fruit characters, mapped onto the combined tree show patterns of widespread parallel evolution and reversals—or possibly the effects of reticulations. Allopolyploidy has been suggested by previous workers and there are some indications of this in our results. Geum andicola appears in different well supported groups in the two separate analyses. This may be caused by inheritance of chloroplast DNA from one parental species and homogenization of ribosomal DNA from the other. Also, the intricate fruit type present in, for example, the type species of Geum, G. urbanum, appears to have evolved twice from progenitors with plumose styles. We propose the name Colurieae for this entire clade and the name Geinae for the group of herbaceous perennials.
Relationships among Halimolobos, Mancoa, Pennellia, and Sphaerocardamum have been controversial. Higher level studies, using cpDNA data from the chloroplast encoded ndhF and trnL intron, suggested that some species of these genera represent a monophyletic group: the halimolobine clade. The research presented here focuses on the halimolobine clade with denser intra and inter-specific sampling. The primary aims of the project were: (1) to further test the monophyly of the halimolobine clade; (2) to test the monophyly Halimolobos, Mancoa, Pennellia, and Sphaerocardamum; and (3) to study the evolution of morphological characters in the clade. Data were generated from the trnL-F region, nrDNA ITS, pistillata intron one, and 17 non-molecular characters. The difficulties associated with incorporating these data into simultaneous analyses are discussed and a strategy is presented. Separate and simultaneous analysis confirmed a monophyletic core group of halimolobine species. The strict consensus tree contained five well-supported halimolobine subclades: Sphaerocardamum, Pennellia plus Arabis tricornuta, Mancoa bracteata plus M. foliosa, a narrowly defined Halimolobos, and a clade consisting of a subset of Halimolobos and Mancoa species. Individual morphological characters vary in their utility for classification of the group. However, the majority of the characters provide some grouping information within the halimolobine clade.
Circumscriptions of the genus Hibiscus and the tribe Hibisceae (Malvaceae) are based on morphological features that are not unique in the family. An examination of the literature regarding putatively ancestral morphological features revealed that Hibiscus and Hibisceae may be defined by shared ancestral features, and thus are unlikely to be monophyletic groups. These phylogenetic hypotheses were tested using two chloroplast DNA sequences (a coding region—ndhF, and a non-coding region—the rpl16 intron). Several genera usually placed in Hibisceae were found to occupy positions sister to the rest of the family, as was predicted from our reevaluation of their morphological features. Although the earliest divergences in the family were not resolved by chloroplast DNA topologies alone, several morphological features, when analysed in combination with ndhF, suggested a possible resolution of the basal polytomy. These early divergences are represented by extant genera with relatively restricted distributions, which all possess Australasian species that are sister to more widespread and diverse lineages. This suggests the novel hypothesis that eastern Gondwana may be the centre of origin of the family. The pollen fossil record is consistent with this possibility, but does not support it unambiguously. Unexpectedly the tribes Decaschistieae and Malvavisceae as well as other genera of Hibisceae nest within Hibiscus. Nomenclatural upheavals concerning Hibiscus, one of the world's most popular horticultural plant genera, will be difficult to avoid.
We have conducted a phylogenetic analysis of 57 taxa including 127 accessions of Acer to determine the geographical origin and the presumptive progenitor species of Acer takesimense and A. okamotoanum, two endemics of the Korean island Ullung-do. Sequence analyses of the trnL intron and the trnL-trnF intergenic spacer of chloroplast DNA show a close relationship of A. takesimense to A. pseudosieboldianum from mainland Korea. Acer okamotoanum probably has evolved from Korean individuals of A. mono and not from Japan where A. mono is also native. AFLP data further support the proposed relationships and indicate a substantial loss of genetic diversity of A. takesimense when compared with the progenitor populations from mainland Korea. Both sequence and AFLP data put A. takesimense populations into a monophyletic group, suggesting that they speciated in Ullung Island from a single introduction from Korean peninsular populations. Populations of A. okamotoanum, on the other hand, show a higher degree of shared alleles with at least two mainland populations of their presumptive progenitor A. mono, perhaps indicating multiple origins of the latter endemic species.
Davidia, a genus that is now endemic to China, played a prominent role in Paleocene vegetation of mid-latitude North America that previously was overlooked. Davidia antiqua (Newberry) comb. nov. is now known from co-occurring leaves and fruits at eight localities in the Fort Union Group of North Dakota, Montana, and Wyoming. The leaves, for more than a century called Viburnum antiquum (Newberry) Hollick, conform to extant Davidia in the long petiole, cordate base, pinnate venation, basal secondary veins with regular branches to the margin, typically blunt, large marginal dentations with medial vein insertion, and closely spaced percurrent tertiaries. Fruits are borne singly on otherwise staminate inflorescence heads. The peduncle bears two prominent scars, well below the head, interpreted as the attachment points of large bracts. The fruit stones are ellipsoidal, composed of fibers, with six to eight single-seeded locules, each with an elongate dorsal germination valve. Vascular bundles are not axial, but are scattered through the septae. Although only two-thirds the size of the fruits of extant Davidia involucrata Baillon, and less prominently sculptured, the fossil fruits correspond closely to the extant ones in morphology and anatomy. Similar leaf and fruit impressions occur together in Paleocene deposits of eastern Russia, but additional work is required to determine if they represent the same species as the North American material. This work establishes that extant Davidia had evolved by the Paleocene, prior to the first known occurrences of Nyssa in the Eocene, and was a contemporary of the extinct nyssoid genus Amersinia. The available stratigraphic record thus implies rapid evolution of Nyssoids within the early Tertiary, or may be taken to indicate that this group of Asterids began its diversification in the Cretaceous.
The phylogeny of Diapensiaceae was investigated by analysis of morphology and molecular data from three genomes; the internal transcribed spacers (ITS) of nuclear ribosomal DNA, rbcL and ndhF from the chloroplast genome, and matR from the mitochondrial genome. Compared to earlier investigations this study is based on a larger data set and has also a larger taxonomic sample that includes representatives of all recognized genera of the family. The results show that Galax is the sister group to all other genera of the family, and that Pyxidanthera is sister to the rest at the next higher node. The relationships between Berneuxia, Diapensia, and Shortia are unresolved. The monophyly of Diapensia is not supported, but has not been tested with molecular data. The monophyly of Shortia is well supported, with S. soldanelloides as sister to the other species. The results indicate that the first diversification in the family occurred in North America with a subsequent diversification of the genera Galax and Pyxidanthera, respectively, and that the ancestor of the remaining genera had an eastern distribution. The small American distribution of Shortia galacifolia is interesting considering the East Asian distribution of its closest relatives, S. uniflora and S. exappendiculata.
Cladistic analyses using parsimony jackknifing were performed on DNA sequences from the chloroplast gene rbcL to elucidate phylogenetic relationships in Primula and its relationships to other genera of the Primulaceae. A total of 51 species from Primulaceae and 34 species from related families were included. The results showed that the genus Primula was not monophyletic because the genera Dodecatheon, Cortusa, Sredinskya, and Dionysia had their closest relatives within Primula. The results also showed that the genera Pomatosace and Douglasia were derived relatives of Androsace. Diagnostic characters such as leaf vernation, pollen type, and base chromosome numbers were discussed.
Nuclear ribosomal DNA internal transcribed spacers (ITS) and chloroplast matK gene were sequenced for 23 species of Actinidia, the genus of kiwifruit. Neither ITS nor matK phylogeny supports monophyly of any of the four sections of the genus. Species of section Leiocarpae form a paraphyletic group at the base of both gene trees. Species of sections Maculatae, Strigosae, and Stellatae plus A. rufa of section Leiocarpae form a monophyletic group, which is consistent with the morphological feature of presence of lenticels on fruit exocarps. Within this clade, however, each of the three sections is polyphyletic on both gene phylogenies. Polymorphic ITS sequences were cloned from 17 of 27 accessions sampled in this study. The polymorphic sequences that are distantly related on the phylogeny may have derived from hybridization or introgression. The infrageneric classification of Actinidia should be revised on the basis of a robust phylogenetic reconstruction inferred from additional molecular, morphological, and cytological data.
Lycium (Solanaceae) is a genus of ∼ 75 species found worldwide inhabiting arid to semi-arid environments. Phylogenetic relationships were inferred for 25 species of Lycium and three closely-related Grabowskia species using sequences of the internal transcribed spacer (nr-ITS) regions of nuclear ribosomal DNA and 27 morphological characters. The nr-ITS and morphological data sets were congruent and a combined analysis showed strong support for a clade containing several North American species that have distinctive floral and fruit morphologies. In addition, there was strong support for a single origin of gender dimorphism among North American Lycium species. Inclusion of a dimorphic species from South Africa suggests that gender dimorphism has evolved independently among African Lycium. Results strongly suggest that Lycium is not monophyletic, but includes the genus Grabowskia. Further, North American Lycium are paraphyletic and current sectional circumscriptions for the American species are inadequate.