Current Circumscription Research Articles

Sequencing of historic and modern specimens reveals cryptic diversity in Nothogenia (Scinaiaceae, Rhodophyta)

:Nothogenia fastigiata has been reported to exhibit great morphological variability and has been considered to be widely distributed in the Southern Hemisphere. To test its current circumscription, sequences from type material of N. fastigiata and other species currently synonymized with it were compared to those from recent collections of this and other species in the genus. Eight distinct species previously subsumed under the name N. fastigiata were identified. Multiple specimens from southern Chile and a single specimen from Campbell Island (subantarctic New Zealand) were conspecific with type material of N. fastigiata from the Falkland Islands. For other species, molecular analyses of recent collections using the nuclear ITS1-5.8S-ITS2 region of the ribosomal cistron, the chloroplast rbcL and psbA genes and the mitochondrial COI gene indicated a strong geographic pattern to species relationships. Other specimens identified as N. fastigiata from Chile represented up to five species, including N. chilensis and N. fragilis, based on sequences of type material; these Chilean species occurred on a monophyletic branch. We also recognized N. lingula comb. nov. from Tasmania, which is closely related to N. fastigiata, based on sequences of type material. Specimens from mainland New Zealand identified as N. fastigiata fell into a distinct clade with New Zealand N. pulvinata and represented a previously undescribed species, described here as N. neilliae sp. nov. Another New Zealand species, N. pseudosaccata, was distantly related to N. variolosa from Auckland Island and other subantarctic islands south of New Zealand. The New Zealand species were more closely related to South African N. erinacea and N. ovalis than to species of Nothogenia from Chile, including N. fastigiata, although bootstrap support for this interpretation was weak. These genetic data demonstrate that matching DNA sequences from archival Nothogenia material to modern specimens can be used to identify and define new and old cryptic species.

Phylogenetic relationships of Coronidium, Xerochrysum and several neglected Australian species of “Helichrysum” (Asteraceae: Gnaphalieae)

AbstractA molecular phylogeny of selected Australian native Gnaphalieae (Asteraceae) is inferred from nuclear ribosomal ETS and ITS and chloroplast matK‐psbA, psbA‐trnH and ycf6‐psbM sequences to test the reciprocal monophyly of the genera Coronidium and Xerochrysum and to taxonomically place several species currently treated as part of Helichrysum. Ribosomal and chloroplast phylogenies are topologically incongruent, but the latter are poorly resolved and poorly supported. Ribosomal and total evidence data suggest that the C. scorpioides group makes Coronidium in its current circumscription polyphyletic. Even without this species group, remaining Coronidium is inferred to be paraphyletic to Xerochrysum. Helichrysum macranthum and H. milligani are shown to be part of Xerochrysum and formally transferred to that genus. A lectotype is designated for H. milliganii. Helichrysum leucopsideum is shown to be affiliated with C. adenophorum and C. waddelliae while H. rutidolepis is confirmed to be part of the C. scorpioides group. In contrast, the affiliations of H. calvertianum, H. oligochaetum and H. pumilum cannot currently be resolved with confidence.

Generic boundaries of Leucochrysum and Waitzia (Asteraceae: Gnaphalieae)

The Australasian clade of Gnaphalieae (Asteraceae) is an ecologically diverse group of species whose generic limits and phylogenetic relationships are still partly unresolved. Previous studies including hybridisation trials, morphological characterisation and preliminary phylogenetic analyses within the Gnaphalieae have suggested that two genera, namely, Waitzia and Leucochrysum, require further investigation into their generic boundaries. To explore the phylogenetic relationships of both genera, the present study used a combination of morphological and molecular approaches. The character traits of herbarium specimens from 14 species and six infraspecific taxa of Waitzia, Leucochrysum and Anemocarpa were examined. Chloroplast (psbA–trnH) and nuclear ribosomal ITS and ETS sequences were generated for phylogenetic analysis. Our findings support Waitzia in its current circumscription as a monophyletic group, whereas Leucochrysum was found to be polyphyletic. Leucochrysum fitzgibbonii was found to be the sister group of Waitzia and shares characters of the involucral bracts, indumentum and growth habit with that genus. The species is formally transferred to the genus Waitzia as W. fitzgibbonii.

Phylogenetic and cladistic analyses of the enigmatic generaBituminaria and Cullen (Fabaceae) in Turkey

Three taxa of the genus Psoralea L. growing naturally in Turkey and the outgroup taxa belonging to the closest genera Vicia L., Cicer L., and Astragalus L. were subjected to molecular and quantitative morphological analyses in order to characterize their phylogenetic relationships. Both the taxonomical and the molecular characteristics of the tribes Psoraleeae (Bituminaria Heist. ex Fabr., Cullen Medik.), Vicieae (Vicia), Astragalae (Astragalus), and Cicereae (Cicer) were clearly revealed for the first time with the inter-simple sequence repeat (ISSR) method. The phylogenetic relationships were determined with 253 ISSR band scores and 125 quantitative morphological character measurements. The numerical and molecular data sets were analyzed with NTSYSpc and Minitab software. Based on these data, the current circumscription of the genus Psoralea was reevaluated and compared with outgroups in Turkey. Consequently, the closely related genera of Bituminaria and Cullen clearly occur in Turkey instead of the genus Psoralea.

Acacieae Benth. (Leguminosae, Mimosoideae) in Minas Gerais, Brazil

Acacieae Benth. (Leguminosae–Mimosoideae) comprises more than 1450 species and is composed of five genera in the current circumscription: Senegalia Raf., Mariosousa Seigler & Ebinger, Vachellia Wight & Arn., Acacia Mill., and Acaciella Britton & Rose. This work describes the diversity of the Tribe Acacieae in the state of Minas Gerais. The studies were based on the analysis of specimens from herbaria, field observations, and the collection of botanical materials. The study provides descriptions, illustrations, an identification key, common names, and data on the geographic distribution and flowering and fruiting of these species. Eighteen species belonging to this tribe were recognized in the state. For the first time, we report the occurrence of Senegalia velutina DC. in Minas Gerais. The species are distributed in the three biomes in the state: Atlantic Forest, Cerrado, and Caatinga. Senegalia bahiensis (Benth.) Seigler & Ebinger, S. giganticarpa (G. P. Lewis) Seigler & Ebinger, S. lacerans (Benth.) Seigler & Ebinger, S. lewisii (Bocage & Miotto) L. P. Queiroz, S. limae (Bocage & Miotto) L. P. Queiroz, S. martii (Benth.) Seigler & Ebinger, S. paganucci (Willd.) Seigler & Ebinger, S. pteridifolia (Benth.) Seigler & Ebinger, S. serra (Benth.) Seigler & Ebinger, and S. velutina have been designated for inclusion on the list of endangered species in Minas Gerais.

Phylogenetic relationships and species delimitation among the taxa with propagula in Pseudotaxiphyllum (Plagiotheciaceae, Bryophyta)

AbstractThe current circumscription of the eight closely related morphospecies with propagula in Pseudotaxiphyllum Z. Iwats. is extremely unsatisfactory because of the ill‐defined delimitation of the species concepts. In order to determine the systematic positions of these closely related species, a phylogenetic reconstruction was carried out based on molecular analyses of two genomic compartments (chloroplast ndhB, rpl16, trnG, trnL‐F, and nuclear ribosomal internal transcribed spacer (nrITS)) together with a haplotype network analysis and species delimitation assessments by thorough morphological studies. The results of the present study show that P. elegans (Brid.) Z. Iwats. was closely related to P. laetevirens (Dixon & Luisier ex F. Koppe & Düll) Hedenäs and both species together with P. maebarae (Sakurai) Z. Iwats. were resolved as monophyletic clades. Pseudotaxiphyllum arquifolium (Bosch & Sande Lac.) Z. Iwats., P. densum (Cardot) Z. Iwats., P. fauriei (Cardot) Z. Iwats., the Asian populations of P. distichaceum (Mitt.) Z. Iwats. and P. pohliaecarpum (Sull. & Lesq.) Z. Iwats. are morphologically identical. At least three cryptic lineages with undifferentiated morphological or geographical pattern were inferred from this species complex. We propose that the above‐mentioned morphospecies be synonymized under P. distichaceum, and the American ‘P. distichaceum’ be replaced by a new name, P. subfalcatum (Austin) X. Q. Li, Q. Zuo & Y. F. Wang, stat. nov. Pseudotaxiphyllum obtusifolium Z. Iwats. & B. C. Tan was treated as P. distichaceum (Mitt.) Z. Iwats. var. obtusifolium (Z. Iwats. & B. C. Tan) X. Q. Li, Q. Zuo & Y. F. Wang, stat. nov.

Molecular data support Orianthera: a new genus of Australian Loganiaceae

Results from recent molecular systematics have indicated that Logania R.Br. in its current circumscription is polyphyletic, with each of its two constituent sections, Logania sect. Logania and L. sect. Stomandra, representing distinct monophyletic clades. Logania sect. Stomandra is here raised to generic status as Orianthera C.S.P.Foster & B.J.Conn since the name Stomandra has already been applied to a genus in Rubiaceae. Orianthera differs from Logania sensu stricto based on the place of insertion of the stamens (in the sinus between the corolla lobes in Orianthera; in the middle of the corolla tube in Logania); the anthers being exserted from the corolla mouth in Orianthera (anthers included in Logania); the shape of the apex of each calyx lobe (acute to tapering, with membranous margin in Orianthera; obtuse in Logania, without membranous margin); and the sexuality of flowers (bisexual in Orianthera; unisexual in Logania). A key to genera in the tribe Loganieae is provided and 13 species (all new combinations) are enumerated for Orianthera.

Pollen morphology and taxonomic implications in Jacquemontia Choisy (Convolvulaceae)

Jacquemontia is one of the larger genera in Convolvulaceae, with around 120 species, and is considered taxonomically difficult. The family is eurypalynous and pollen morphology has been considered as an important taxonomic character. Pollen morphology of 43 species, representing all morphological groups of Jacquemontia, was analysed with light microscopy and/or scanning electron microscopy. Three pollen types were characterised. These pollen types do not corroborate the current circumscription of sections in Jacquemontia, which is based on inflorescence structure. Conversely, however, some macro-morphological features are discussed that support groups defined on the basis of pollen analysis.

A molecular phylogeny of Acronychia, Euodia, Melicope and relatives (Rutaceae) reveals polyphyletic genera and key innovations for species richness

We present the first detailed phylogenetic study of the genus Melicope, the largest genus of the Citrus family (Rutaceae). The phylogenetic analysis sampled about 50% of the 235 accepted species of Melicope as well as representatives of 26 related genera, most notably Acronychia and Euodia. The results based on five plastid and nuclear markers have revealed that Acronychia, Euodia and Melicope are each not monophyletic in their current circumscriptions and that several small genera mainly from Australia and New Caledonia need to be merged with one of the three genera to ensure monophyly at the generic level. The phylogenetic position of the drupaceous Acronychia in relation to Melicope, which has capsular or follicular fruits, remains unclear and Acronychia might be a separate genus or a part of Melicope. The seed coats of Melicope, Acronychia and related genera show adaptations to bird-dispersal, which might be regarded as key innovations for species radiations. Euodia and its relatives, which lack these adaptations, include only about 20 species while the Melicope–Acronychia group consists of about 340 species. The drupaceous genera Comptonella, Dutaillyea, Picrella and Sarcomelicope are nested within Melicope and need to be merged with Melicope. The expanded genus is a prime example of the artificial classification system of Engler, who defined Rutaceous subfamilies mainly based on gynoecial and fruit characters.

Molecular delimitations in the Ehretiaceae (Boraginales)

Major taxa of Ehretiaceae (including parasitic Lennoaceae) have not all been included in previous molecular phylogenetic analyses. As a result, the generic limits and their circumscriptions have not been satisfactorily resolved, despite its importance for floristic studies. To clarify which monophyletic groups can be recognized within the Ehretiaceae, sequences from one nuclear (ITS) and three plastid loci (rps16, trnL–trnF, trnS–trnG) were obtained from 67 accessions tentatively assigned to the Ehretiaceae (including 91 new GenBank entries) and covering the known diversity of the group. In phylogenetic analyses, Ehretiaceae were monophyletic when Lennoaceae were included and segregated into nine monophyletic lineages that correspond to accepted, morphologically distinct taxonomic units, namely Bourreria (s.l., paraphyletic in its current circumscription if not including Hilsenbergia), monotypic Cortesia, Ehretia (s.l., paraphyletic in its current circumscription if not including Carmona and Rotula), Halgania, monotypic Lennoa, Lepidocordia, Pholisma, Rochefortia, and Tiquilia. Bourreria and Ehretia have representatives in both the Old World and the New World, but all other taxa are restricted to the tropical and subtropical Americas (Cortesia, Lennoa, Lepidocordia, Pholisma, Rochefortia, Tiquilia) or Australia (Halgania). The historical biogeography of Ehretiaceae can be explained by few colonization events. The molecular trees are also discussed with respect to fruit evolution, where the fusion of endocarp parts may have taken place several times independently.

A pollinator shift explains floral divergence in an orchid species complex in South Africa.

Floral diversification driven by shifts between pollinators has been one of the key explanations for the radiation of angiosperms. According to the Grant-Stebbins model of pollinator-driven speciation, these shifts result in morphologically distinct 'ecotypes' which may eventually become recognizable as species. The current circumscription of the food-deceptive southern African orchid Eulophia parviflora encompasses a highly variable monophyletic species complex. In this study, two forms were identified within this complex that differ in distribution, floral morphology, scent chemistry and phenology, and a test was made of whether these differences represent adaptations for different pollinators. Multivariate analysis of floral and vegetative traits revealed that there are at least two discrete morphological forms in the species complex. Field observations revealed that each form is pollinated by a different insect species, and thus represent distinct ecotypes. The early-flowering coastal form which has long spurs and floral scent dominated by sesquiterpene compounds is pollinated exclusively by the long-tongued bee Amegilla fallax (Apidae, Anthophorinae), while the late-flowering inland form with short spurs and floral scent dominated by benzenoid compounds is pollinated exclusively by the beetle Cyrtothyrea marginalis (Cetoniinae; Scarabaeidae). Choice experiments in a Y-maze olfactometer showed that beetles are preferentially attracted to the scent of the short-spurred form. A spur-shortening experiment showed that long spurs are required for effective pollination of the bee-pollinated form. Although it was initially thought likely that divergence occurred across a geographical pollinator gradient, plants of the long-spurred form were effectively pollinated when transplanted to an inland locality outside the natural coastal range of this form. Thus, the underlying geographical basis for the evolution of ecotypes in the E. parviflora complex remains uncertain, although early flowering in the long-spurred form to exploit the emergence of naïve bees may restrict this form to coastal areas where there is no frost that would damage flower buds. Later flowering of the short-spurred form coincides closely with the emergence of the pollinating beetles following winter frosts. This study identifies a shift between bee and beetle pollination as the main driver of floral divergence in an orchid species complex. Floral scent and spur length appear to be key traits in mediating this evolutionary transition.

Invasion of the South American dry diagonal: What can the leaf anatomy of Pitcairnioideae (Bromeliaceae) tell us about it?

The current circumscription of Pitcairnioideae (Bromeliaceae) comprises the genera Deuterocohnia, Dyckia, Encholirium, Fosterella, and Pitcairnia. The leaf anatomy in Bromeliaceae provides interesting features that have helped to resolve taxonomic problems and can reveal several adaptations to the environment. We combined information on the leaf anatomy of 114 species of the five genera of this family with a phylogenetic approach to the Pitcairnioideae, seeking micromorphological synapomorphies that could aid in the recognition of each clade, in addition to tracing its evolutionary history. Through this analysis it was possible to identify characteristics that distinguish a xeric clade and mesic genera. As a general pattern, each main cladogenic event in Pitcairnioideae is marked with an anatomical synapormorphy. The presence of xeric synapomorphies (especially CAM, fibrous hypodermis, and ad- and abaxial aquiferous parenchyma) apparently played an essential role in allowing species of Deuterocohnia, Dyckia, and Encholirium to occupy the South American dry-diagonal.

Sinopsis de las especies austro-americanas del género Nassella (Poaceae, Pooideae, Stipeae)

Nassella is an American genus which, according to its current circumscription, includes about 116 species, distributed from Canada to Argentina and Chile. It is characterized by its florets with the lemma conspicuously convolute, with an apical conspicuous or inconspicuous crown, and the palea shorter than the lemma; furthermore, the lemma presents a distinctive epidermal pattern. The aim of this work is to provide a synopsis of the 99 species of Nassella which grow in southern South America, comprising Argentina, Bolivia, southern Brasil, Chile, Paraguay and Uruguay. A key to identify the species, mainly based on floret characters, is given. For each species, the current synonyms, geographic distribution, phenology, observations, and illustrations are presented. Nassella barbinodis is accepted, Nassella linearifolia is a new synonymous of Nassella caespitosa. Lectotypes were here designed for the following taxa: Danthonia nardoides, Piptochaetium collinum, P. gibbum, P. laevissimum, Stipa arechavaletae, S. barbinodis, S. breviculmis, S. calchaquia, S. carettei, S. clarazii var. bulbosa, S. curicoana, S. debilis var. papillosa, S. duriuscula, S. hispida, S. hyalina, S. julietii, S. longiglumis, S. macrathera, S. manicata var. media, S. mendocina, S. pratensis, S. pseudopampagrandensis, S. rupestris, S. tenuis, S. trachysperma, S. trichocaulos, and S. uspallatensis. A neotype is designated for S. filiculmis.

Comparative foliar epidermal micromorphology of Southern African Strychnos L. (Loganiaceae): taxonomic, ecological and cytological considerations

The micromorphology of the leaf epidermis of 11 species across four sections of southern African Strychnos was investigated using light microscopy and scanning electron microscopy. In addition to this, preliminary genome size was assessed with flow cytometry. Qualitative and quantitative results are presented for stomata, trichome and cuticular wax features with an emphasis on the abaxial epidermal surface. A correlated combination of these microscopic features was able to distinguish successfully among the 11 species of Strychnos found in the subcontinent. However, micromorphological evidence does not support the current circumscription of the sections. The often-confused S. gerrardii and S. madagascariensis are distinguishable on leaf micromorphological grounds. Stomata and trichome features show remarkable patterns that largely correlate with the ecological distribution of Strychnos species as either forest or savanna inhabitants. The significant variability in stomatal length across species is hypothesized to be indicative of possible existence of variable ploidy levels within the genus in southern African. However, preliminary genome size analyses with flow cytometry appear to be inconclusive.

Lejeunea Subelobata and Lejeunea Drummondii (Jungermanniopsida) in Australasia

Abstract Lejeunea subelobata Carrington & Pearson has been regarded as a synonym of L. drummondii Taylor, but the two species differ in patterns of variation in lobule morphology, shapes of the gynoecial bracteole, female bract underleaf and vegetative underleaves; in stem anatomy, and ecology. Lejeunea subelobata is a rheophyte from south-east Australia, Tasmania, and New Zealand that grows primarily as a lithophyte on rock within and around waterways, in association with basicolous substrates particularly basalt, rhyolite and andesite. Lobules in L. subelobata are always explanate, the female bract underleaf is obovate, underleaves are rotund and remote, and the stem medulla has 19-26 cells with small concave trigones. Lejeunea drummondii is, in its current circumscription, an ecologically and morphologically malleable taxon confined to Australia. The relationship between L. drummondii and plants from New Zealand described as L. epiphylla Colenso nom. illeg. requires further investigation.

Anatomy of scapes, bracts, and leaves of Paepalanthus sect. Diphyomene (Eriocaulaceae, Poales) and its taxonomic implications

Paepalanthus sect. Diphyomene comprises 18 species with a convoluted taxonomic history. Aiming to correlate anatomical structures with the systematics of this group and its relatives, we studied the anatomy of scapes, reproductive axis bracts, and leaves of 20 Paepalanthus species. Bracts and leaves show differences in epidermal cell thickening; mesophyll width; vascular bundle arrangement; presence or absence of a hypodermis; types of cells in the vascular bundle sheath extensions; margin shape and composition; and presence or absence of aquiferous parenchyma. Scapes differ in contour, rib number, and pith size. Some diagnostic characters found are presence of aquiferous parenchyma and absence of vascular bundle sheath extensions in leaves of P. urbanianus; vascular bundles decreasing in size towards the margin of leaves and bracts, and scapes with a triangular contour in P. flaccidus; scapes with nine ribs in P. acanthophyllus and ten in P. macer. All anatomical features are summarized in tables. These results aid in the identification and characterization of the species of P. sect. Diphyomene. They also support the current section circumscription, reinforcing the relevance of the anatomical characters in order to define natural groups.

About the circumscription of <i>Celosia argentea</i> (Amaranthaceae) and the related Linnaean taxa

As part of the revision of the genus Celosia Linnaeus (1753: 205) for the treatment of Amaranthaceae for the Euro+Med plantbase project and the New Flora of Italy (Iamonico, in prep.), it has been necessary to establish the identity of C. argentea Linnaeus (1753: 205) in comparison with the related taxa C. cristata Linnaeus (1753: 205), C. castrensis Linnaeus (1762: 297) and C. margaritacea Linnaeus (1762: 297) (Feng et al. 2009). A first step was the typification of the names (Iamonico & Jarvis 2012). Here the current circumscription of C. argentea in comparison with C. cristata, C. castrensis and C. margaritacea are discussed using relevant literature and morphological data of collections (70 specimens from the Herbaria B, BAR, FI, K, KUFS, PE, RO, LINN andTROY were examined).

Molecular phylogeny, origin and taxonomic implications of the tribe Cacteae (Cactaceae)

This study aimed to test the phylogenetic relationships of the tribe Cacteae, the generic circumscription within the tribe, in particular, the monophyly of the genus Ferocactus, and to provide a biogeographical hypothesis about the origin of Cacteae. The analysis included 135 species from all of the 27 accepted genera and four outgroup species. Five chloroplast regions were sequenced, aligned, and coded postulating gaps, simple sequence repeats (SSRs), and inversions as potential synapomorphies, and their contributions to phylogenetic reconstruction were evaluated. The phylogenetic analyses recovered 63% of the genera as monophyletic. The contribution of rpl16, trnL-F and psbA to the phylogenetic signal was higher than in the two more slowly evolving genes (rbcL, matK), but the gaps and SSRs supported some of the genera. This result differs from those of previous phylogenetic studies in which less than 35% of the genera were recovered as monophyletic. In this work, Astrophytum and Echinocactus were re-circumscribed with five and four species, respectively. Turbinicarpus was found to be polyphyletic; 11 species correspond to Turbinicarpus s.str., whereas a highly supported clade corresponded to Rapicactus, and three species need further study. Contrary to its current circumscription, Ferocactus was not supported as monophyletic because it is polyphyletic concerning Glandulicactus, Leuchtenbergia, Stenocactus and Thelocactus. We recognize this group of genera as the Ferocactus clade in which the species share the presence of scales in the pericarpel and ribbed stems, whether tuberculated or not. The Cacteae seem to have originated in the Sierra Madre Oriental and then dispersed to the Mexican Plateau, where radiation and diversification occurred at the boundaries of the Miocene–Pliocene Epoch. The development of the Mexican Plateau and the Trans-Mexican Volcanic Belt may have favoured the isolation of the Cacteae. A taxonomic diagnosis is presented for the tribe Cacteae and 18 genera that we now recognize.

A taxonomic revision of Pleiochiton (Melastomataceae, Miconieae)

The genus Pleiochiton has frequently been recognized by dubious characters and seldom treated in taxonomic and floristic surveys. Nevertheless, monophyly of the genus has been highly supported by recent molecular and morphological data, and it can be morphologically recognized by the epiphytic growth and succulent roots. Following the current circumscription, the genus has 12 species, all endemic to the Atlantic Forest sensu stricto in eastern Brazil. The species occur in well conserved middle elevation forests and most are narrowly distributed, with four recorded from only a single locality. In this paper we present a taxonomic revision of the genus and provide an identification key, distribution maps, descriptions, and illustrations for all species. The new species P. amorimii is described, and the known distribution of the genus is expanded northwards, into the “brejos de altitude” of Pernambuco state.

A new genus of Ptilodactylidae (Coleoptera: Byrrhoidea) in mid-Cretaceous amber from Myanmar (Burma)

ABSTRACT The first Mesozoic fossil of the beetle family Ptilodactylidae Laporte, 1836 (Byrrhoidea) is formally described and figured from a male preserved in latest Albian amber from Myanmar. Aphebodactyla rhetine n. gen., n. sp., is distinguished from its modern relatives and is only the second fossil species yet formally described in the family. The fossil intermingles putatively derived features of various ptilodactylid subfamilies, suggesting that the current circumscription of these lineages is in dire need of revision.