Gagea bohemica (Liliaceae), a highly variable monotypic species within Gagea sect. Didymobulbos

Abstract

Gagea bohemica s.l. (Liliaceae) consists of two morphologically extreme forms (saxatilis and bohemica) which depending on the varying opinions of the authors are considered as separate species, subspecies or as a single variable species. In this study, morphological (form and length of perianth segments, pilosity of pedicles and peduncles) and molecular data (cpDNA trnL–trnF IGS) of 55 samples corresponding to 43 populations from Western Europe to the Mediterranean area and eastern Caucasus were investigated. G. bohemica (Zauschn.) Schult. & Schult. f. represents a highly variable monotypic species from both morphological and karyological (2n = 24, 36, 48, 60, 72) aspects. Based on the molecular and morphological data presented here, a differentiation between specific and infraspecific taxa is not possible. We hypothesize that the morphological variability of this species is largely influenced by different site conditions and ploidy level.     

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.     

Hybridization drives speciation in Gagea (Liliaceae)

Hybridization seems to play an important role in speciation of Gagea Salisb., a genus which is characterised by polyploid taxa lines and in which diploids (2n = 24) appear only to be common in basal sections. Hybrid detection was applied utilising direct and cloning nrDNA ITS data (ITS1, 5.8S rDNA, ITS2) combined with neighbour and ribotype networks and discussed in connection with previously published cpDNA, morphological and karyological data of the authors. We have evidence of the hybrid origin of taxa within the section Gagea (G. pomeranica, G. megapolitana) and the monophyletic clade of sections Didymobulbos and Fistulosae (G. microfistulosa, G. polidorii, G. cf. bohemica). Morphologically and karyologically differentiated Gagea megapolitana and G. pomeranica, adapted to synanthropic habitats, represent both hybrids of G. pratensis × G. lutea. Gagea microfistulosa represents a hybrid of G. villosa × G. fragifera; Gagea polidorii could represent the reverse hybrid. G. glacialis is also closely related to the latter complex.     

Homoploid hybrid speciation in Doronicum L. (Asteraceae)? Morphological,karyological and molecular evidences

Abstract

The first unambiguous documentation of hybridism in the genus Doronicum (Senecioneae – Asteraceae) is reported. All our morphological, karyological and molecular data concur to indicate that Doronicum × minutilloi Peruzzi hybr. nov. (2n = 60) is a hybrid growing in Monti Aurunci (Central Italy), originated from the spontaneous crossing D. orientale Hoffm. (2n = 60) × D. columnae Ten. (2n = 60). This new hybrid shows a slightly higher morphological, karyotypic and ribotypic affinity with D. columnae, but shares a trnL-trnF IGS haplotype with D. orientale, and co-occurs with the latter species only; it has reduced fertility and a high potential for vegetative propagation through rhizome fragmentation. Our results led us to suspect in fieri homoploid hybrid speciation.     

Phylogenetic relationships of Italian Bellevalia species (Asparagaceae), inferred from morphology,karyology and molecular systematics

The seven Bellevalia species and subspecies known from Italy, representing about 10% of the genus and three out of six sections, were studied. An integrated morphological, karyological and molecular approach was used to infer phylogenetic and systematic relationships among them. B. romana (the generitype) is the most distinctive species on karyotype asymmetry grounds. B. boissieri and B.dubia, usually considered as subspecies of one species (the latter endemic to Sicily), deserve specific status based on biparental nrDNA markers (internal transcribed spacer, ITS), since they do not form a single clade. The allotetraploid endemic B. pelagica, morphologically similar to B. romana, is sister to the latter under parsimony, both in morphological and ITS trees; it is also related with B. dubia, based on karyotype asymmetry and a uniparental cpDNA marker (trnL^(UAA)–trnF^(GAA) IGS (intergenic spacer)). A second allotetraploid endemic, B. webbiana, is closely related, on morphological, karyological and molecular grounds, with B. boissieri and B. ciliata, and also with B. trifoliata, three species that might all involved in its origin. B. sect. Conicae Feinbr. and sect. Nutantes Feinbr. are here typified, the former (type: B. ciliata) is most likely a synonym of the latter (type: B. trifoliata).     

Bothriospermum longistylum sp. nov. (Boraginaceae) from north China

Based on field investigations as well as morphological and molecular systematic studies we found a new species of Bothriospermum which can be easily distinguished from all other known congeneric species by its unlobed faucal appendages and very long styles. We conducted molecular phylogenetic analyses based on a combined dataset from nrITS, plastid rps16, trnL‐trnF and trnG‐trnS regions. The results indicated that the new species indeed belongs in Bothriospermum and that it is well separated from other congeneric clusters, but that the genus Bothriospermum is paraphyletic with Nihon and Thyrocarpus clusetered within it. As a result, Bothriospermum longistylum sp. nov. is described and illustrated here. A revised key to species of Bothriospermum and a distributional map are also presented.     

The genus Gymnospermium (Berberidaceae) in Italy: identity and relationships of the populations at the western limit of the genus range

Abstract

Gymnospermium is a small genus of 7–12 taxa subject to diverging taxonomic treatments and distributed from east China to the Balkans. The recent discovery of Gymnospermium in the S-Apennines posed questions about origin and identity. Accordingly, we performed a systematic investigation by means of morphological, karyological and molecular tools. All populations were diploid with 2n = 14 as for the Balkan G. scipetarum (incl. G. maloi), and also morphology suggested a close affinity to the latter. However, the Italian populations differed from typical G. scipetarum by the lower stamen:petal length and style:carpel length. By including all European and most Asian taxa in a phylogenetic analysis, we shed new light into the species-level relationships in this genus. In the combined ITS-trnL-F phylogeny, two major clades were retrieved. One included the central Asian and eastern European taxa plus the Greek endemic G. peloponnesiacum sister to G. odessanum, and one the Balkan and Apennine populations. Such findings further corroborated that the Apennine plant belong to G. scipetarum. The native status of the Italian population is supported by exclusive SNPs in both ITS1 and trnL-F sequences. Along with morphological evidence, this allows to refer it to the new subspecies G. scipetarum subsp. eddae.     

Using molecular data to test the monophyly of Lallemantia in the subtribe Nepetinae (Mentheae,Lamiaceae)

Phylogenetic relationships among the species of Lallemantia and its close allies (Lamiaceae, Mentheae) were investigated using nuclear (ITS) and plastid (trnL, trnL/F, trnS/G, rpl32, and rpl32-trnL) DNA sequences. Phylogenetic results from Bayesian and parsimony analyses show that (1) Lallemantia is monophyletic, (2) Hymenocrater is nested within Nepeta, and (3) Lallemantia is more closely related to Dracocephalum than other genera in Nepetinae. Based on the molecular results, the genus Lallemantia comprises two disparate lineages, with each lineage supported by distinct morphological characters (e.g. floral structures and pollen grains).     

Minor differences with big consequences: Reproductive patterns in the genus Gagea (Liliaceae)

Reproductive patterns in ten species of Gagea Salisb. were compared by counts and measurements of bulbs, bulbils and flowers in large cohorts including all life stages. Two types of bulbils were found: taxa with “type I bulbils” start to develop a single to several bulbils as soon as the replacement bulb has reached a certain diameter and then continue to form them indefinitely throughout the life of the plant. “Type II bulbils” are only temporarily produced in immature, non-flowering plants of some species, but not in fully grown, flowering individuals, a phenomenon termed “reproductive switch”. Patterns of bulbil formation are species-specific: G. davlianidzeae, G. nigra, G. peduncularis, G. pratensis, and G. spathacea produce only type I bulbils; G. angelae, G. fedschenkoana and G. lutea develop only type II bulbils. Both bulbil types occur simultaneously in G. fragifera and G. villosa. The quantitative investigations demonstrate the existence of species-specific thresholds for the development of bulbils as well as flowers. Compared to the adult volume of the replacement bulb (where 90% of all plants flower), both types of bulbils have usually low thresholds: 0–5% (type I, all but one species) and 3–13% (type II). Inflorescences develop if plants attain between 38 and 60% of the adult bulb volume. Minor changes in patterns of bulbil formation and thresholds for their development may ensure survival of highly sterile taxa (e.g. G. spathacea, G. fragifera). This, in turn, can facilitate speciation in the genus driven by both hybridization and polyploidization.     

Refugia and phylogeography of Taiwania in East Asia

Aim The East Asia endemic Taiwania cryptomerioides Hayata is an iconic and relictual monotypic conifer whose main extant populations are now restricted to the Yunnan–Myanmar border, northern Vietnam and Taiwan. It has also been reported from several localities in Guizhou, Hubei and Fujian Provinces, China. Its fossil record indicates that, while it was more widely distributed in the Northern Hemisphere and grew under a range of different ecological conditions, it has remained almost unchanged in its morphology for over 100 Myr. We investigate whether these remaining extant, disjunct populations have diverged genetically; when such a divergence may have occurred; and which, if any, of the extant populations exhibit refugial characteristics. Location East Asia. Methods Sequences of five chloroplast DNA markers (petG–trnP, trnH–psbA, trnV–trnM, trnC–ycf6 and trnL–trnF) from all extant populations of T. cryptomerioides were analysed to reveal their phylogeography. Molecular clock models with fossil calibrations were used to estimate divergence times between extant populations. Results Extremely low nucleotide diversity was found in the overall population (π = 0.00077) with only nine haplotypes distinguished. The mainland Asia populations share one major ancestral haplotype. The insular populations in Taiwan all possess a unique haplotype with at least an eight‐mutational‐step difference to the mainland Asia haplotype. Molecular clock estimations demonstrated that the mean divergence time between the predominant insular population haplotype and the mainland Asia haplotype occurred at c. 3.23–3.41 Ma, followed by a split into Vietnamese and Yunnan–Myanmar populations (c. 1.0–1.39 Ma). Main conclusions Strong genetic differentiation exists between insular (Taiwan) and mainland Asia populations. The split between insular and mainland haplotypes can be dated back to the end of the Pliocene. The Yunnan–Myanmar border area, northern Vietnam and Taiwan are identified here as potential refugia for T. cryptomerioides. Other populations in mainland China are unlikely to be the result of historical fragmentation and their origins require further investigation.     

Molecular phylogeny of the endemic fern genera Cyrtomidictyum and Cyrtogonellum (Dryopteridaceae) from East Asia

Cyrtomidictyum Ching and Cyrtogonellum Ching are two eastern Asian endemic genera whose taxonomic affinities and phylogenetic relationships have long been controversial. The main uncertainty surrounds the separation of the two genera from the species-rich genus Polystichum. Here we present a phylogenetic study focusing on the phylogenetic relationships of these polystichoid ferns. We reconstructed the relationships based on DNA sequence variation in four chloroplast genome regions, rbcL, atpB, and the intergenic spacers (IGS) rps4-trnS and trnL-trnF. Maximum likelihood and Bayesian inference analyses confirm earlier results that were based on less comprehensive taxon sampling and either only a single gene (rbcL) or two IGS (rps4-trnS and trnL-trnF). Cyrtomidictyum is the sister of the clade of polystichoid ferns that includes Cyrtogonellum, Cyrtomium subser. Balansana and three sections of Polystichum. Cyrtogonellum groups with several species of Polystichum, and constitutes the sister taxon to Polystichum sect. Sphaenopolystichum. We support the recognition of Cyrtomidictyum as circumscribed initially, rather than expansion of the genus to include either several Polystichum species or Cyrtogonellum, some Polystichum and Cyrtomium species. The monophyly of Cyrtomidictyum is supported by morphological characters such as once-pinnate leaves, free venation, prolongated leaf apices, and exindusiate sori. Two synapomorphic indels in the chloroplast genome, one 15-bp deletion in rps4-trnS, and one 3-bp insertion in trnL-trnF further differentiate Cyrtomidictyum from other polystichoid ferns. The close affinity of Cyrtogonellum to section Sphaenopolystichum of Polystichum s.s. is highly supported by molecular data. However, no shared morphological characters or molecular indels have been detected, although the distinctness of Cyrtogonellum is shown by a 13-bp insertion in the rps4-trnS alignment.     

Phylogeny of Androcymbium (Colchicaceae) based on morphology and DNA sequences

The inclusion of species of Colchicum within Androcymbium in a previous cpDNA phylogeny of the Colchicaceae, questioned the monophyly of Androcymbium, and it was proposed to unite the two genera in Colchicum. Here we expand the previous phylogenetic analyses of Androcymbium by increasing the taxon sampling and adding more data. The analysis include 29 of the 57 species of Androcymbium, more cpDNA (trnL intron, trnL-trnF IGS, trnY-trnD IGS, and trnH-psbA IGS), and nDNA (RNApol2 intron 23) regions, and morphological and life-history traits data. Both parsimony and Bayesian inference were used. According to our data there is no reason to expand Colchicum to include Androcymbium, but we support the inclusion of Bulbocodium and Merendera within Colchicum. Morphology and life history traits are the main arguments in favor of recognizing Androcymbium as a well-circumscribed genus. In the phylogeny two Androcymbium groups are clearly differentiated: (1) one including species from Western and Eastern South Africa, Namibia, and North Africa, and (2) one including species from the north west of South Africa and south of Namibia.     

Systematics of Gagea and Lloydia (Liliaceae) and infrageneric classification of Gagea based on molecular and morphological data

Our study represents the first phylogenetic analyses of the genus Gagea Salisb. (Liliaceae), including 58 species of Gagea and 6 species of the closely related genus Lloydia Salisb. ex Rchb. Our molecular results support the infrageneric classification of the genus Gagea in sections according to Levichev and demonstrate that Pascher's subdivision of this genus into two subgenera can no longer be upheld. Certain Gagea sections (e.g., Gagea, Minimae, and Plecostigma) are well supported by cpDNA and nrDNA data. Gagea sect. Fistulosae is closely related to G. sect. Didymobolbos. Gagea sect. Graminifoliae and G. sect. Incrustatae are closely related to G. sect Platyspermum. The analyses support the monophyly of Gagea and Lloydia collectively. The molecular analyses reveal the basal position of G. graeca in proportion to all other species of Gagea and Lloydia investigated. Minor morphological differences could be established between both genera which support their close relationship.     

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.     

基于形态学特征和分子数据的中国缺齿藓科初步研究

为探讨缺齿藓类与真藓科、提灯藓科的系统关系,理清缺齿藓科的系统位置和中国缺齿藓科分类问题,该研究以中国分布的缺齿藓科植物和相关类群4 000余份标本为材料,进行详细的形态学研究,并选用其中35种、40份样品的4个DNA片段(rps4、trnG、trnL-trnF、atpB-rbcL)联合数据用于分子系统分析,采用邻接法(NJ)和最大似然法(ML)构建分子树。结果表明:(1)在分子树中,缺齿藓类与真藓科植物分别聚在具有高支持率的不同分支上,叶形、叶细胞等形态学特征也有较大差异,缺齿藓类应从广义的真藓科分出。(2)在分子树中,虽然缺齿藓类与提灯藓科植物聚在同一分支中,但无形态学的共源性状,二者不应视为一个单系类群。(3)缺齿藓科是一个自然类群,缺齿藓科内属间存在着密切的系统关系,缺齿藓科的主要识别特征为:植物体小型,茎常分枝;叶形和叶细胞为丝瓜藓型(Pohlia-like),披针形至长椭圆形,中上部细胞狭长,线状菱形或蠕虫形;生殖苞多生于新生枝顶;蒴齿为互生双齿层,常有不同程度的退化或一层蒴齿缺失,稀双层蒴齿缺失。(4)中国缺齿藓科包含有5属,即缺齿藓属(Mielichhoferia)、丝瓜藓属(Pohlia)、拟丝瓜藓属(Pseudopohlia)、合齿藓属(Synthetodontium)和小叶藓属(Epipterygium),目前为止共计34种(含种下分类单位)。     

First record of <Emphasis Type="Italic">Gagea szovitsii</Emphasis> in Central Europe

Morphological characters, habitat preference, and currently known distribution of the species Gagea szovitsii (A.F. Láng) Besser, a new indigenous vascular plant species of Central Europe, are presented. The plant was found in alkali grasslands of the south-eastern part of the Great Hungarian Plain (SE Hungary). Currently, this can be regarded to the westernmost occurrence of this pontic species. Both G. szovitsii and its closest relative G. bohemica are briefly characterized here with respect to their identification, ecology and distribution. Original illustrations on G. szovitsii are presented. The paper firstly emphasizes the difference of reproductive strategy between G. szovitsii and G. bohemica; the former reproduce itself primarily sexually via seeds, while the latter reproduce itself in asexual way principally by bulbils. Taking the paleo-environmental history of its habitat into consideration, the species can be regarded as an ancient, indigenous Pontic-Pannonian steppe element of Hungary.     

基于ITS和trnL-trnF序列的草木樨种群遗传多样性研究

以白花草木樨(Melilotus alba)和黄花草木樨(Melilotus officinalis)18个地理种群植物为材料,用ITS序列和trnL-trnF序列研究了2种草木樨不同种群间的遗传多样性。结果表明:(1)trnL-trnF序列对位后长度为459bp,其中包括6个变异位点,6个简约信息位点,G+C含量为33.1%;ITS序列对位后长度为714bp,其中包括5个变异位点,3个简约信息位点,G+C含量为48.9%。(2)在基于trnL-trnF序列构建的系统发育树中,2种草木樨能够形成单系分支,说明trnL-trnF序列在草木樨中的鉴别能力较强。(3)单倍型多样性以及核苷酸多样性分析表明,黄花草木樨的遗传多样性高于白花草木樨。     

Phylogenetic relationships between disjunctly occurring groups of Tristicha trifaria (Podostemaceae)

Aim To reveal the phylogeographic relationship of disjunct specimens of Tristicha trifaria (Bory ex Willd.) Spreng., a member of the Podostemaceae river‐weed family, which is distributed exceptionally widely, but disjunctly, in Africa and the Americas. Location Brazil, Mexico, Ghana, Tanzania and Madagascar. Methods The chloroplast matK and rbcL genes, a trnK intron, the trnS‐trnG intergenic spacer (IGS), the two IGSs of trnT‐trnL‐trnF, a trnL intron, and nuclear ribosomal ITS regions were sequenced and analysed. Phylogenetic analyses were conducted using maximum likelihood and maximum parsimony methods. Results The T. trifaria samples analysed were separated into two groups in a rooted tree based on a combined matK/rbcL/ITS dataset; one contained the West African and all of the American samples, and the other contained the East African and Madagascan samples. An unrooted tree obtained from a combined analysis of all the chloroplast DNA and nuclear ITS data showed that a sample from West Africa was sister to an American T. trifaria group. Main conclusions The American and West African T. trifaria are closely related, despite the great distance between their locations. This observation, along with a tree of the whole Tristichoideae subfamily and estimated divergence times, suggests that an ancestor of T. trifaria migrated from Asia to Africa during the early Tertiary, and that this was followed by further westward migration to the Americas at the end of the Miocene or in the early Pliocene.