Phylogeny of Carpinus and subfamily Coryloideae (Betulaceae) based on chloroplast and nuclear ribosomal sequence data

Phylogenetic studies were conducted for Carpinus and the subfamily Coryloideae (Betulaceae) using sequences of the chloroplast matK gene, the trnL-trnF region (trnL intron, and trnL [UAA] 3' exon-trnF [GAA] intergenic spacer) and the psbA-trnH intergenic spacer, and the nuclear ribosomal ITS regions. The combined analyses of the three chloroplast regions suggest that Coryloideae is monophyletic; Ostryopsis is sister to the Carpinus - Ostrya clade; Corylus is monophyletic and sister to the Ostrya - Carpinus - Ostryopsis clade; Ostrya is paraphyletic; and within Carpinus, species of sect. Carpinus from eastern Asia form a monophyletic group, whereas the positions of C. betulus from Europe and C. caroliniana from eastern North America are unresolved within the Carpinus clade. The cpDNA tree generated in this study is largely congruent with the previously published ITS results, but the ITS tree places Carpinus sect. Distegocarpus as sister to the Ostrya - Carpinus sect. Carpinus clade. Future work is needed to examine the relationships within the Ostrya - Carpinus clade, evaluate the generic status of Ostrya, and test the phylogenetic position of Ostryopsis.     

Phylogenetic Framework for Trema (Celtidaceae)

We used ITS and trnL sequence data, analyzed separately and combined by MP, to explore species relationships and concepts in Trema (Celtidaceae), a pantropical genus of pioneer trees. Whether Trema is monophyletic or includes Parasponia is still unresolved. Three clades within Trema received moderate to high support, one from the New World and two from the Old World, but their relationships were not resolved. In the New World, specimens of T. micrantha formed two groups consistent with endocarp morphology. Group I, with smaller brown endocarps, is a highly supported clade sister to T. lamarckiana. Group II, with larger black endocarps, is poorly resolved with several subclades, including the highly supported T. integerrima clade. Both Old World clades contain Asian and African species, with three or more species in each region. Trema orientalis is not monophyletic: specimens from Africa formed a highly supported clade sister to T. africana, while those from Asia were sister to T. aspera from Australia.     

Phylogeny of Castanea (Fagaceae) based on chloroplast trnT-L-F sequence data

Species in the genus Castanea are widely distributed in the deciduous forests of the Northern Hemisphere from Asia to Europe and North America. They show floristic similarity but differences in chestnut blight resistance especially among eastern Asian and eastern North American species. Phylogenetic analyses were conducted in this study using sequences of three chloroplast noncoding trnT-L-F regions. The trnT-L region was found to be the most variable and informative region. The highest proportion of parsimony informative sites, more and larger indels, and higher pairwise distances between taxa were obtained at trnT-L than at the other two regions. The high A+T values (74.5%) in the Castanea trnT-L region may explain the high proportion of transversions found in this region where as comparatively lower A+T values were found in the trnL intron (68.35%) and trnL-F spacer (70.07%) with relatively balanced numbers of transitions and transversions. The genus Castanea is supported as a monophyletic clade, while the section Eucastanon is paraphyletic. C. crenata is the most basal clade and sister to the remainder of the genus. The three Chinese species of Castanea are supported as a single monophyletic clade, whose sister group contains the North American and European species. There is consistent but weak support for a sister–group relationship between the North American species and European species.     

Phylogenetic relationships within Pappophoreae s.l. (Poaceae: Chloridoideae): Additional evidence based on ITS and trnL-F sequence data

Historically, Pappophoreae included the genera Cottea, Enneapogon, Kaokochloa, Pappophorum and Schmidtia. Some authors consider this tribe as a well-supported monophyletic group; while other evidences reveals Pappophoreae as polyphyletic, with Pappophorum separated from the rest of the tribe. When the latter happens, it can form a clade with Tridens flavus. Molecular phylogenetic analyses of the subfamily Chloridoideae have included few species of Pappophoreae; therefore, further research involving more representatives of this tribe is needed. With the aim of providing new evidence to help clarify the phylogenetic position of Pappophorum and its relationships with other genera of the tribe and the subfamily Chloridoideae, eight new sequences of ITS and trnL-F regions of Pappophoreae species were generated. These sequences were analyzed together with other available sequence data obtained from GenBank, using maximum parsimony and Bayesian inference, for individual (trnL-F or ITS) or combined trnL-F/ITS data sets. All analyses reveal that Pappophoreae is polyphyletic, with Pappophorum separated from the rest of the tribe forming a well-supported clade sister to Tridens flavus.     

The phylogenetic relationships of Cynoglottis (Boraginaceae- Boragineae) inferred from ITS, 5.8S and trnL sequences

A molecular phylogenetic analysis of Cynoglottis was performed to evaluate previous hypotheses based on non-molecular evidence concerning the position of this genus within Boraginaceae tribe Boragineae. ITS-5.8S and trnL_UAA sequences from the nuclear and chloroplast non-coding genomes were obtained for four Cynoglottis taxa and selected members of the related genera Anchusa, Anchusella, Gastrocotyle, Brunnera and Pentaglottis. Cynoglottis is monophyletic, but neither trnL nor ITS support a close relationship with Brunnera, unlike previously supposed on morphological grounds. Brunnera is, instead, related to the southwestern European monotypic genus Pentaglottis, with which it forms a basal clade. ITS-5.8S sequences show that Anchusa thessala, a southeastern European annual species of Anchusa subg. Buglossellum, is sister to Cynoglottis and that the two taxa form a clade which also includes the Balkan endemic Gastrocotyle macedonica. Species of Anchusa subg. Anchusa form a separate lineage with high bootstrap support, suggesting that this heterogeneous genus is paraphyletic with respect to Cynoglottis. ITS sequences also discriminate between the Balkan-Apenninic diploid C. barrelieri and the Anatolian tetraploid C. chetikiana, albeit with low support. The molecular results are discussed in the light of karyological, morphological and chorological aspects.This work has been supported by M.I.U.R. 40% 2003 and the University of Firenze.     

The position ofCastrilanthemum Vogt & Oberprieler and the phylogeny of Mediterranean Anthemideae (Compositae) as inferred from nrDNA ITS and cpDNAtrnL/trnF IGS sequence variation

Sequences of the nrDNA internal transcribed spacer (ITS) region and the cpDNAtrnL/trnF intergenic spacer (IGS) region were analysed for 41 Mediterranean and Eurasian representatives of the Anthemideae (Compositae) to ascertain the systematic position of the unispecific genusCastrilanthemum Vogt & Oberprieler and to study the phylogeny of the Anthemideae in the Mediterranean region. Both markers consistently point to the close relationship ofCastrilanthemum with the W Mediterranean generaLeucanthemopsis (Giroux) Heywood andProlongoa Boiss., forming a strongly supported monophyletic group (theLeucanthemopsis-group which also comprises the unispecific genusHymenostemma (Kunze) Willk.). Results also demonstrate that subtribes Achilleinae, Leucantheminae, and Matricariinae sensu Bremer & Humphries are non-monophyletic. Besides results from sequence variation, a marked 5bp-deletion intrnL/trnF IGS divides all these subtribes into more basal subgroups which are related to each other and to the large Eurasian generaTanacetum L. andAnthemis L., and a monophyletic group of closely related and more advanced subgroups which also contain the monophyletic Chrysantheminae sensu Bremer & Humphries. For this second group a W Mediterranean centre of diversification is suggested, however, its sister-group relationships within the basal grade of generic groups remain unclear.     

Pollination by fungus gnats (Diptera: Mycetophilidae) and self-recognition sites in Tolmiea menziesii (Saxifragaceae)

Coleeae (Bignoniaceae) are a tribe almost entirely restricted to Madagascar. Coleeae have previously been placed in neotropical Crescentieae due to species with indehiscent fruits, a character otherwise unusual in Bignoniaceae. A phylogeny based on three chloroplast regions (ndhF, trnT-L spacer, trnL-F spacer) identifies a monophyletic Coleeae that is endemic to Madagascar and surrounding islands of the Indian Ocean (Seychelles, Comores and Mascarenes). African Kigelia is not a member of Coleeae, rather it is more closely related to a subset of African and Southeast Asian species of Tecomeae. The molecular phylogeny indicates that indehiscent fruit have arisen repeatedly in Bignoniaceae: in Coleeae, Kigelia and Crescentieae. The characteristic fleshy fruits of species of Coleeae likely arose autochthonously in Madagascar. Within Coleeae Colea and Ophiocolea are sisters, Phyllarthron is sister to Colea + Ophiocolea, and Rhodocolea is sister to the rest of the tribe.     

Phylogeny of Rhododendron section Vireya (Ericaceae) based on two non-coding regions of cpDNA

Section Vireya (Blume) Copel.f. is one of the most morphologically diverse groups of the genus Rhododendron. Vireyas have a unique distribution for the genus, being predominantly found throughout the Malesian Archipelago. The alpha taxonomy of section Vireya is relatively well understood and taxa are easily distinguished from other rhododendrons by their general appearance. Defining characteristics of the section the possession of seeds with tailed appendages at both ends, the twisting of capsule valves after opening, placentas that separate as thread-like structures from the central axis as the capsule opens are all subject to exceptions. Phylogenetic analyses of two cpDNA regions, psbA-trnH and trnT-trnL intergenic spacers are reported. The results of each analysis were generally congruent, with clades relating strongly to geographic areas. Section Vireya is monophyletic with the inclusion of at least one species of section Rhododendron. Only two of the seven subsections currently circumscribed are monophyletic: Malayovireya Sleumer and Siphonovireya Sleumer. ``Euvireya', all subsections excluding the paraphyletic subsection Pseudovireya, is monophyletic and includes two major clades, one restricted to eastern Malesia and the other to the western and middle Malesia.     

Phylogeny of the Madagascan endemic family Didiereaceae

A molecular phylogeny of the Didiereaceae was produced through parsimony analysis of chloroplastrpl16 intron andtrnL-trnF andtrnT-trnL intergenic spacer sequences of all eleven species of the Didiereaceae and several outgroup taxa from the Portulacaceae. Results indicated that: 1) the Didiereaceae were embedded within the Portulacaceae, withCalyptrotheca as the sister group of the family; 2) present generic limits were supported; 3)Alluaudiopsis was the most basal lineage; 4) at least two separate episodes of polyploidization within the genusAlluaudia had occurred, and 5) unusually low amounts of variation were present in rapidly evolving noncoding plastid sequences.     

Marbleseeds are gromwells – Systematics and evolution of Lithospermum and allies (Boraginaceae tribe Lithospermeae) based on molecular and morphological data

Phylogenetic relationships are complex within the Lithospermeae, a large subgroup of the Boraginaceae s.str. The relationships of New World Lasiarrhenum, Macromeria, Nomosa, Onosmodium, Perittostoma, and Psilolaemus to subcosmopolitan and much larger Lithospermum have not been critically investigated in the recent past. No molecular data on the phylogeny of these genera and Lithospermum have so far been published. We investigated the relationships within Lithospermeae using three loci (nuclear ITS plus 5.8S rRNA, chloroplast trnL-F-spacer, and trnS-G-spacer) and micromorphological character traits (pollen, nutlets). Lithospermum s.l. constitutes the sistergroup of Asian Ulugbekia and is monophyletic only when its American segregates “Macromeria”, monotypic Nomosa, and Onosmodium are included. Both the African and the South American species groups of Lithospermum are monophyletic, but North American representatives are not resolved in a single clade. Morphological characters that have been considered as important for generic delimitation in the past (such as large, yellow corollas without faucal scales, particular pollen types, coarsely veined leaves, shrubby habit) have evolved in at least two only distantly related lineages within Lithospermum s.l. The reduction of American “Macromeria”, Nomosa, and Onosmodium as well as Asian Ulugbekia under Lithospermum is proposed to render the latter monophyletic. This redefined Lithospermum s.l. appears to have undergone a type of recent “island radiation” in the Americas, reflected in a morphological diversity far exceeding that found in the Old World.     

基于5个基因片段的野胡麻属系统位置研究

对单种属野胡麻属(原隶属于广义玄参科)及其可能近缘类群广泛取样,选择合适外类群,通过对4个叶绿体基因联合数据(trnL-F、rps16、rbcL、rps2)、核基因ITS片段、叶绿体基因与核基因ITS片段联合数据,进行最大简约法和贝叶斯法分析,探讨野胡麻属在科级系统位置及其与近缘类群系统发育关系。结果表明,所有系统树都支持野胡麻属先和肉果草属构成姐妹群关系,叶绿体基因联合系统树支持率分别为97%[Bootstrap(BS)]和100%[Posterior probability(PP)];ITS系统树支持率分别为99%(BS)和100%(PP);叶绿体基因和ITS联合系统树支持率均为100%(BS和PP)。野胡麻属、肉果草属与通泉草属一起构成一单系群,叶绿体基因联合系统树、ITS系统树、叶绿体基因和ITS联合系统树的支持率均为100%(BS和PP)。形态学证据也支持野胡麻属、肉果草属和通泉草属这3个属的近缘关系。本研究结果支持单种属野胡麻属隶属于透骨草科的通泉草亚科,与肉果草属亲缘关系最近,这两个属进而与通泉草属近缘,可能隶属于通泉草属内,与岩白翠亲缘关系较近,也可能与通泉草属互为姐妹群关系。     

Molecular phylogeny of Old WorldTrifolium (Fabaceae), based on plastid and nuclear markers

Phylogenies of Old WorldTrifolium species were constructed using nucleotide sequence data of the internal transcribed spacers (ITS) of nuclear ribosomal DNA and chloroplast DNA restriction site data from PCR-amplified genes and genic regions (rbcL,trnK, andrpoC1–C2). Biogeography, morphological evolution, and the existing classification forTrifolium were examined. The genusTrifolium is strongly supported as monophyletic, however, only one small section (Chronosemium) is monophyletic, although the data are in conflict regarding its placement. The two largest sections of the genus, Sects.Lotoidea andTrifolium, are not supported as monophyletic, as currently circumscribed. Many members of Sect.Lotoidea are basal within the genus, supporting previously-proposed hypotheses concerning plesiomorphic morphological characters and a Mediterranean-Mideast biogeographic origin of the genus.     

Molecular phylogeny of Phebalium (Rutaceae: Boronieae) and related genera based on the nrDNA regions ITS 1+2

Parsimony analyses of the internal transcribed spacer regions of nuclear ribosomal DNA (ITS 1 & ITS 2) for 38 taxa sampled from the Phebalium group (Rutaceae: Boronieae) and two outgroups confirm that, with the exception of Phebalium sensu stricto and Rhadinothamnus, six of the currently recognised genera within the group are monophyletic. The data indicate that Phebaliums. str. is paraphyletic with respect to Microcybe, and Rhadinothamnus is paraphyletic with respect to Chorilaena. Rhadinothamnus and Chorilaena together are the sister group to Nematolepis. Drummondita, included as an outgroup taxon, clustered within the ingroup as sister to Muiriantha and related to Asterolasia.The phylogeny suggests that the evolution of major clades within a number of these genera (e.g. Phebalium) relates to vicariance events between eastern and south-western Australia. Leionema is an eastern genus, with the most basal taxon being the morphologically distinct Leionema ellipticum from northern Queensland. Leionema also includes one species from New Zealand, but this species (as with some others) proved difficult to sequence and its phylogenetic position remains unknown. Taxonomic changes at the generic level are recommended.The authors wish to thank Paul G.Wilson, PERTH, for advice and discussion, and Paul Forster, BRI, for collecting and providing material of Leionema ellipticum. The project was supported by a Melbourne University Postgraduate Award (to BM), the Australian Biological Resources Study (ABRS), Australian Systematic Botany Society and Wolf Den (Australia) Investments.     

利用DNA片段测序方法探究枳属和富民枳的分类地位

富民枳(Poncirus polyandra)属于芸香科(Rutaceae)枳属(Poncirus Raf.)。自发表以来,分类地位一直备受争议,其中在Flora of China中认为富民枳为柑橘杂交种(Poncirus polyandra),把枳属归并于柑橘属(Citrus)。该研究选取枳属的富民枳、枳(Poncirus trifoliata)及柑橘属下8个种共10个种47个个体作为研究材料,以九里香(Murraya exotica)为外类群,利用3个叶绿体片段(trn L-trn F、trn S-trn G、rbc L)、ITS片段和1个单拷贝核基因(Chr 5)数据构建系统发育树,探究枳属和富民枳的分类地位。结果表明:基于3个叶绿体片段数据构建的最大似然树(ML)和贝叶斯树(BI)的拓扑结构基本一致,10个物种聚为两大分支,即柑橘属的8个物种聚为一大分支,富民枳和枳聚为另一大分支。其中,富民枳所有个体聚为一小单系分支,枳的所有个体聚为一小单系分支,支持枳属和富民枳独立存在。2个核DNA片段数据结果显示,枳属的两个种与柑橘属的8个物种聚在一个大分支里,无法确立枳属的单系地位,但富民枳的9个个体聚在一起,暗示富民枳在遗传上是一个独立的类群。综上研究认为,无论是叶绿体DNA数据还是核DNA数据均支持富民枳是一个独立的物种,但核DNA数据不支持枳属成立。     

Phylogenetic relationships among species and genera of Lycoperdaceae based on ITS and LSU sequence data from north European taxa

Phylogenetic relationships, limits of species, and genera within Lycoperdaceae, were inferred by use of ITS and LSU nu-rDNA sequence data. Lycoperdaceae was confirmed as monophyletic, and Mycenastrum corium as a sister taxon to the ingroup. Four major clades were identified and received weak to moderate support and correspond with the genera Lycoperdon, Bovista, Calvatia, and Disciseda. The Lycoperdon clade includes species from Lycoperdon, Vascellum, Morganella, Handkea, Bovistella, and Calvatia. The structure within the Lycoperdon clade is unresolved and several clades are more or less unsupported, which suggests treating the supported Lycoperdon clade as the genus Lycoperdon. L. nigrescens and L. caudatum occur on single branches and their phylogenetic positions could not be resolved. The phylogenetic analyses identified 31 species of Lycoperdon, 11 species of Bovista, six species of Calvatia, and two species of Disciseda. In Lycoperdon three new species were recognized. A new species closely related to B. limosa is identified and discussed. A classification of Lycoperdaceae is proposed based on the results of the phylogenetic analyses. Morphological characters of species within and among identified clades are discussed.     

Extensive length variation in the cpDNA trnT-trnF region of hemiparasitic Pedicularis and its phylogenetic implications

The cpDNA trnT-trnF region, a molecular marker widely used in the phylogenetic reconstruction at lower taxonomic levels, is relatively conserved in size and structure. In this region single length variation over 100 bp is much less common than small deletion for congeneric species of angiosperms. Here we examined evolutionary patterns of the trnT-trnF region in 43 species of Pedicularis, a species-rich genus with adaptive radiation. Four independent large deletions, varying from 203 to 297 bp in length, were detected from nine species of the genus, which might result from slipped-strand mispairing. These deletions occurred in different locations of the cpDNA region and in different clades of the phylogenetic tree, indicating that the deletion of large cpDNA fragments may be very frequent in the hemiparasitic lineage of the family Orobanchaceae. Parsimony analyses showed that section Cyathophora of Pedicularis, endemic to the Sino-Himalayan region, was a strongly supported monophyletic group. This section could have a recent origin followed by rapid radiation, considering that it is characterized by a large deletion in the trnT-trnF region and a relatively low interspecific sequence divergence.     

The phylogenetic positions of the conifer genera Amentotaxus,Phyllocladus, and Nageia inferred from 18s rRNA sequences

To determine the evolutionary positions of the conifer genera Amentotaxus, Phyllocladus, and Nageia, we obtained 18S rRNA sequences from 11 new taxa representing the major living orders and families of gymnosperms. With the published Chlamydomonas as an outgroup, phylogenetic analyses of our new data and available sequences indicate that (1) the Gnetales form a monophyletic group, which is an outgroup to the conifers, (2) the conifers are monophyletic, (3) Taxaceae, Cephalotaxaceae, Cupressaceae, and Taxodiaceae form a monophyletic group, (4) Amentotaxus is closer to Torreya than to Cephalotaxus, suggesting that Amentotaxus is better to be classified as a member of Taxaceae, (5) Phyllocladus, Dacrycarpus, Podocarpus, and Nageia form a monophyletic group, and (6) Pinaceae is an outgroup to the other families of conifers. Our finding that Phyllocladus is a sister group of the Podocarpaceae disagrees with the suggestion that the phylloclade of the genus is an ancient structure and that the genus is a terminal taxon within the Podocarpaceae. The genus Nageia is more closely related to Podocarpus than to Dacrycarpus and was derived from within the Podocarpaceae. In conclusion, our data indicate that in conifers, the uniovulate cone occurred independently in Taxacaeae and Cephalotaxaceae, and in Podocarpaceae after the three families separated from Pinaceae, and support the hypothesis that the uniovulate cone is derived from reduction of a multiovulate cone.Correspondence to: S.-M. Chaw     

Historical biogeography and phylogenetic relationships of the genus Chamaecyparis (Cupressaceae) inferred from chloroplast DNA polymorphism

The genus Chamaecyparis comprises five species and one variety native to Taiwan, Japan, Canada, and USA, which demonstrates a classical eastern Asian, western North American, and eastern North American disjunct distributional pattern. The phylogenetic relationships of the species of Chamaecyparis were inferred by comparing 1130 bp of the combined data set of chloroplast trnV intron and petG-trnP intergenic spacer. The phylogenetic tree shows that Chamaecyparis nootkatensis (Cupressus nootkatensis or Xanthocyparis nootkatensis) is clearly diverged from other Chamaecyparis species. For Chamaecyparis species, C. thyoides is sister to C. formosensis and C. pisifera and these together form a monophyletic group. C. lawsoniana is sister to C. obtusa and C. taiwanensis; and these form another monophyletic group. Homogeneity in evolutionary rates was found among species in these two monophyletic groups. Results indicate the divergent evolution of C. taiwanensis and C. formosensis and molecular evidence in this investigation supports C. taiwanensis as a variety of C. obtusa. Utility of cpDNA intergenic spacer petG-trnP in Chamaecyparis is also discussed. Several biogeographical implications were inferred: (1) at least two divergence events have produced the eastern Asian, and both western and eastern North American disjunct distribution in Chamaecyparis; (2) intercontinental sister species pairs are found in Chamaecyparis; (3) cpDNA divergence between two intercontinental sister pairs of C. thyoides and C. pisifera, and C. lawsoniana and C. obtusa is 2.8% and 1.1%, which suggest an estimated divergence time of 14 and 5.5 million years ago during middle and late Miocene, respectively; (4) cpDNA divergence of two Asian Chamaecyparis groups between C. obtusa and C. taiwanensis, and between C. pisifera and C. formosensis is 0.25% and 0.57%, which suggest an estimated divergence time of 1.3 and 2.9 million years ago during Pleistocene and late Pliocene, respectively; these estimated divergence times suggest a relatively recent migration of Chamaecyparis to Taiwan from the Japanese Archipelago; (5) that climatic deterioration caused the disappearance of Chamaecyparis in continental Asia is probable.     

A molecular phylogeny of the genus Gagea (Liliaceae) in Germany inferred from non-coding chloroplast and nuclear DNA sequences

The systematics of the mainly yellow flowered Gagea species complex (Liliaceae) has long been considered difficult because only a few phenotypic features within this genus and as a result of hypothesized interspecific hybridisation. A molecular phylogenetic study of seven Gagea species (G. bohemica, G. lutea, G. minima, G. pomeranica, G. pratenis, G. spathacea and G. villosa) from Germany has been undertaken, based on plastid DNA sequences (trnL(UAA)-trnF(GAA), psbA-trnH) and on the nuclear ribosomal internal transcribed spacer (ITS). Sequence divergence within the Gagea species ranges up to 15.5% for psbA-trnH, 22.0% for trnL-trnF and 23.7% for ITS (ITS1 + 5.8S rRNA + ITS2). Two subspecies of Gagea bohemica: G. bohemica subsp. saxatilis and G. bohemica subsp. bohemica are characterized by trnL-trnF data and morphological features. Analysis of the ITS region shows that G. pomeranica represents a hybrid of G. pratensis and G. lutea. Lloydia serotina was initially used as an outgroup species, but it was placed within the investigated Gagea species in the psbA-trnH and the trnL-trnF phylogenetic tree.     

A taxonomic reassessment of the Vittiaceae (Hypnales, Bryopsida): evidence from phylogenetic analyses of combined chloroplast and nuclear sequence data

The Vittiaceae are a small family of aquatic mosses that are defined based on gametophytic traits whose interpretation has led to conflicting taxonomic arrangements. Phylogenetic analyses of two cpDNA regions, trnL-trnF and atpB-rbcL, indicate that Vittia is nested within the Amblystegiaceae s. str., suggesting that the family Vittiaceae should not be recognized. Platylomella lescurii appears nested within the Thuidiaceae/Leskeaceae. This suggests that the series of character states shared by Vittia and Platylomella, including a differentiated leaf border, short laminal cells, stiff stems, and a thick costa, are convergent features that arose independently in unrelated lineages of aquatic Hypnales. Within the Amblystegiaceae, phylogenetic analyses of the two cpDNA regions combined with ITS sequence data show that Hypnobartlettia, Vittia elimbata spec. nov., V. pachyloma, and V. salina, despite their strong morphological similarity to aquatic Amblystegium species, form a clade that is sister to the Drepanocladus/Pseudo-calliergon complex. This combined clade is unresolved at a polytomy that includes Amblystegium serpens and a clade including all the other Amblystegium species. The occurrence of A. serpens outside the strongly supported clade including other Amblystegium species suggests that A. serpens may be better accommodated in a distinct genus. Amblystegium serpens is the type species of Amblystegium and thus retains the name. The other species are accommodated in their own genus, Hygroamblystegium, including H. fluviatile, H. humile comb. nov., H. noterophyllum, H. tenax, and H. varium.