The Carboniferous floras of the Iberian Peninsula: A synthesis with geological connotations

A general review is presented of the Carboniferous floral records in the Iberian Peninsula in the context of the geological history and distribution of the different basins. Mississippian floras are found in Sierra Morena, where major strike-slip faults brought in terranes of diverse provenance. Lower Pennsylvanian floras are represented in the Peñarroya-Belmez-Espiel (Córdoba) and Villanueva del Río y Minas (Sevilla) coalfields of SW Spain (also strike-slip controlled), at La Camocha, near Gijón (Asturias), and in other parts of northern Spain. Middle Pennsylvanian is represented near Oporto, but more completely in the Central Asturian Coalfield, as well as other, more limited localities in NW Spain and the Pyrenees. Upper Pennsylvanian (Stephanian Stage-Cantabrian to Stephanian B substages) floras are splendidly represented in NW Spain. Uppermost Pennsylvanian (Stephanian C-Autunian) floras are present in the strike-slip controlled Douro and Buçaco basins of North Portugal, the Pyrenees, Central Spain (Ciudad Real, Guadalajara, Zaragoza), and SW Spain (Guadalcanal and Valdeviar in Sevilla province).A complete succession of megafloral zones is presented. This includes a new Annularia spicata Zone at the top of the Pennsylvanian (equivalent to middle to upper Autunian which has been often attributed to the Lower Permian). The information is summarised in charts compiled from a selection of the most significant species. A number of floral elements are illustrated including the zonal indices. Brief taxonomic comments are provided in the Appendix.     

Stomatal morphology and physiology explain varied sensitivity to abscisic acid across vascular plant lineages

Abscisic acid (ABA) can induce rapid stomatal closure in seed plants, but the action of this hormone on the stomata of fern and lycophyte species remains equivocal. Here, ABA-induced stomatal closure, signaling components, guard cell K⁺ and Ca²⁺ fluxes, vacuolar and actin cytoskeleton dynamics, and the permeability coefficient of guard cell protoplasts (P_f) were analyzed in species spanning the diversity of vascular land plants including 11 seed plants, 6 ferns, and 1 lycophyte. We found that all 11 seed plants exhibited ABA-induced stomatal closure, but the fern and lycophyte species did not. ABA-induced hydrogen peroxide elevation was observed in all species, but the signaling pathway downstream of nitric oxide production, including ion channel activation, was only observed in seed plants. In the angiosperm faba bean (Vicia faba), ABA application caused large vacuolar compartments to disaggregate, actin filaments to disintegrate into short fragments and P_f to increase. None of these changes was observed in the guard cells of the fern Matteuccia struthiopteris and lycophyte Selaginella moellendorffii treated with ABA, but a hypertonic osmotic solution did induce stomatal closure in fern and the lycophyte. Our results suggest that there is a major difference in the regulation of stomata between the fern and lycophyte plants and the seed plants. Importantly, these findings have uncovered the physiological and biophysical mechanisms that may have been responsible for the evolution of a stomatal response to ABA in the earliest seed plants.

Physiological and biophysical evidence for insensitivity of stomata to abscisic acid in ferns and lycophytes supports stomatal responsiveness to abscisic acid evolved after the divergence of ferns.     

Additive partitioning as a tool for investigating the flora diversity in oceanic archipelagos

This paper introduces the integration of additive partitioning with species—area relationships to island biogeography in order to address the question “How are the pteridophyte and spermatophyte native and endemic flora of different oceanic archipelagos partitioned across islands?”.Species richness data of all endemic species and all native species of pteridophytes and spermatophytes were obtained for the Azores, Canaries and Cape Verde in the Atlantic Ocean and Galápagos, Hawaii and Marquesas in the Pacific Ocean. Additive partitioning of species diversity was used to quantify how much of the total diversity of an oceanic archipelago flora (γ-diversity) is due to (i) the mean species richness of the flora of each island (α-diversity), (ii) the variability in species richness of the floras across islands (β_Nestedness) and (iii) the complementarity in species composition of the floras of different islands (β_Replacement). The analysis was separately performed for the native and endemic pteridophyte and spermatophyte floras.The diversity partitioning of the six archipelagos showed large differences in how the flora of each archipelago is partitioned among the α, β_Nestedness and β_Replacement components, for pteridophytes and spermatophytes and for all endemic species and all native species. The α-diversity was more important for all native species than for endemic species and more important for pteridophytes than for spermatophytes, with the Azores showing outstanding high values of α-diversity. The β_Nestedness was higher for pteridophytes than for spermatophytes and higher for endemic species than for all native species in both pteridophytes and spermatophytes. The values of β_Replacement suggested that: (i) the spermatophyte native flora is more differentiated across islands than the pteridophyte native flora and (ii) the pteridophyte endemic flora and, especially, the spermatophyte endemic flora are more differentiated across islands than the corresponding native flora. An outstanding value of β_Replacement for endemic and all native spermatophytes was found in Hawaii, confirming the biogeographical island differentiation in this archipelago.     

Lepidophylloides corumbataensis sp. nov. from the Guadalupian in the Paraná Basin,southern Brazil

A new species of the isoetalean leaf genus Lepidophylloides is described. This Guadalupian species from the Paraná Basin, Lepidophylloides corumbataensis, found as silicified microphylls in the Corumbataí Formation in the municipality of Piracicaba, São Paulo state, in southern Brazil, is the first species of the genus to be formally described for Brazil, and possibly the first for Gondwanaland. This is also the first time that surviving palisade tissue has been found in a species of Lepidophylloides. The new species is compared to known species and shown to be distinct from all previously described from Euramerican and Cathaysian floras. The organization of the xylem in arch-like or crescent-shaped bundles suggests a relation to Cathaysian species. The close association with Lycopodiopsis derbyi stems (which have true leaf scars and must have suffered leaf abscission) suggests that they are different organs from the same species.     

Floral Assemblages and Patterns of Insect Herbivory during the Permian to Triassic of Northeastern Italy

To discern the effect of the end-Permian (P-Tr) ecological crisis on land, interactions between plants and their insect herbivores were examined for four time intervals containing ten major floras from the Dolomites of northeastern Italy during a Permian–Triassic interval. These floras are: (i) the Kungurian Tregiovo Flora; (ii) the Wuchiapingian Bletterbach Flora; (iii) three Anisian floras; and (iv) five Ladinian floras. Derived plant–insect interactional data is based on 4242 plant specimens (1995 Permian, 2247 Triassic) allocated to 86 fossil taxa (32 Permian, 56 Triassic), representing lycophytes, sphenophytes, pteridophytes, pteridosperms, ginkgophytes, cycadophytes and coniferophytes from 37 million-year interval (23 m.yr. Permian, 14 m.yr. Triassic). Major Kungurian herbivorized plants were unaffiliated taxa and pteridosperms; later during the Wuchiapingian cycadophytes were predominantly consumed. For the Anisian, pteridosperms and cycadophytes were preferentially consumed, and subordinately pteridophytes, lycophytes and conifers. Ladinian herbivores overwhelming targeted pteridosperms and subordinately cycadophytes and conifers. Throughout the interval the percentage of insect-damaged leaves in bulk floras, as a proportion of total leaves examined, varied from 3.6% for the Kungurian (N = 464 leaves), 1.95% for the Wuchiapingian (N = 1531), 11.65% for the pooled Anisian (N = 1324), to 10.72% for the pooled Ladinian (N = 923), documenting an overall herbivory rise. The percentage of generalized consumption, equivalent to external foliage feeding, consistently exceeded the level of specialized consumption from internal feeding. Generalized damage ranged from 73.6% (Kungurian) of all feeding damage, to 79% (Wuchiapingian), 65.5% (pooled Anisian) and 73.2% (pooled Ladinian). Generalized-to-specialized ratios show minimal change through the interval, although herbivore component community structure (herbivore species feeding on a single plant-host species) increasingly was partitioned from Wuchiapingian to Ladinian. The Paleozoic plant with the richest herbivore component community, the coniferophyte Pseudovoltzia liebeana, harbored four damage types (DTs), whereas its Triassic parallel, the pteridosperm Scytophyllum bergeri housed 11 DTs, almost four times that of P. liebeana. Although generalized DTs of P. liebeana were similar to S. bergeri, there was expansion of Triassic specialized feeding types, including leaf mining. Permian–Triassic generalized herbivory remained relatively constant, but specialized herbivores more finely partitioned plant-host tissues via new feeding modes, especially in the Anisian. Insect-damaged leaf percentages for Dolomites Kungurian and Wuchiapingian floras were similar to those of lower Permian, north-central Texas, but only one-third that of southeastern Brazil. Global herbivore patterns for Early Triassic plant–insect interactions remain unknown.     

Construction of a bacterial artificial chromosome library from the spikemoss Selaginella moellendorffii: a new resource for plant comparative genomics

Background

The lycophytes are an ancient lineage of vascular plants that diverged from the seed plant lineage about 400 Myr ago. Although the lycophytes occupy an important phylogenetic position for understanding the evolution of plants and their genomes, no genomic resources exist for this group of plants.

Results

Here we describe the construction of a large-insert bacterial artificial chromosome (BAC) library from the lycophyte Selaginella moellendorffii. Based on cell flow cytometry, this species has the smallest genome size among the different lycophytes tested, including Huperzia lucidula, Diphaiastrum digita, Isoetes engelmanii and S. kraussiana. The arrayed BAC library consists of 9126 clones; the average insert size is estimated to be 122 kb. Inserts of chloroplast origin account for 2.3% of the clones. The BAC library contains an estimated ten genome-equivalents based on DNA hybridizations using five single-copy and two duplicated S. moellendorffii genes as probes.

Conclusion

The S. moellenforffii BAC library, the first to be constructed from a lycophyte, will be useful to the scientific community as a resource for comparative plant genomics and evolution.     

Exploring the pteridophyte flora of the Eastern Afromontane biodiversity hotspot

In this review, we explore our current understanding of the fern and lycophyte diversity occurring in the Eastern Afromontane Biodiversity Hotspot (EABH). The review explores the species diversity of this region in the context of the Afromadagascan pteridophyte diversity based on an exhaustive species list assembled in the synopsis of Afromadagascan pteridophytes published by Roux in 2009. The list was updated by incorporating recent progress in our understanding of the taxonomy and phylogeny of these plants. Evidence for a distinct pteridophyte flora occurring in the East African mountain region was discovered using ordination and clustering analyses. This EABH floras shares links to other Afromadagascan pteridophyte floras such as the one in the tropical lowland forests of central and western Africa. These floras share the dominance of species that preferably occur in humid climates whereas other African pteridophyte floras tend to contain a higher proportion of xeric adapted ferns. The phylogenetic composition of the EABH pteridophyte flora was assessed by comparing global versus local proportion of orders, families, and genera. This analysis revealed distinct patterns that are partly caused by the radiation of Blotiella and Triplophyllum besides selective colonization of species pre-adapted to Afromadagascan climates. In situ speciation in the East African tropical mountains may have contributed to the global diversity of widespread genera such as Asplenium and Pteris. In summary, this is the first comprehensive attempt to assess the pteridophyte diversity of the East African mountains providing the framework for future studies on their conservation, ecology, and evolution.     

An introduction to Iranian Collembola (Hexapoda): an?update to the species list

The Collembola fauna of Iran is little known and no comprehensive examination of this group of Hexapoda is available for this region. The only notable work on Collembola was carried out by Cox (1982). Recently, studies on the Collembola fauna have started in several regions. In this paper, publications by different researchers are documented and the species that have been found in different regions of Iran until January 2013 are listed. At present, 112 species, belonging to 18 families and 57 genera are known from Iran.     

Anatomically preserved lepidodendralean plants from lower permian coal balls of northern China: Achlamydocarpon intermedium sp. nov.

Lepidodendralean lycopsids, a dominant component in Late Palaeozoic wetland plant communities, possess a diversity of reproductive structures that are primarily known from the Late Palaeozoic floras of Europe and North America. Here we document an anatomically preserved lepidodendralean lycopsid sporophyll with attached megasporangium from the Lower Permian Taiyuan Formation in Shanxi Province, northern China. The sporophyll has a pedicel onto which the sporangium is attached, and the sporangium is dorsiventrally flattened, proximally dehiscent and longitudinal ridged. The megasporangial wall comprises three zones: an outer uniseriate layer of columnar cells, a middle layer 1–3 cells thick comprising isodiametric parenchymatous cells, and an inner zone 1–3 cells thick of thick-walled cells. The vascular system comprises a single xylem strand surrounded by zone of parenchyma that continues through the pedicel into the lamina. Within the megasporangium a single functional megaspore and three abortive megaspores occur. Features of this specimen conform to Achlamydocarpon Schumacher-Lambry, and comparisons with other species show it shares similarities with A. takhtajanii (Sni.) Schumacher-Lambry and A. varius Taylor and Brack-Hanes. Although the morphology and anatomy of the specimen we describe overlaps with these two species, it is distinct from both leading to the erection of the new species A. intermedium sp. nov. The evolutionary significance of A. intermedium sp. nov. and the identity of its parent plant are considered, and the status and systematic position of “Oriental lepidophytes” from the Cathaysian floras are discussed.     

Lycophytes from the Middle Triassic (Anisian) locality Kühwiesenkopf (Monte Prà della Vacca) in the Dolomites (northern Italy)

Abstract: Generally, lycophytes are not well represented in Anisian floras. Nonetheless, four different genera, each with one species, have been distinguished in the Anisian flora from Kühwiesenkopf (Monte Prà della Vacca), Italy. They were well preserved and yielded leaf cuticles in all four taxa and in situ spores in two of them. Lycopia dezanchei gen. et sp. nov. is the most common form; it is characterized by a dichotomising creeping prostrate rhizome (representing the primary shoot axis) from which arise aerial axes, apically bifurcated and covered with bundles of long leaves. This taxon cannot be attributed to any of the lycophyte orders, but most resembles Lycopodiales. Two representatives of the Isoetales have been found, of which Isoetites brandneri sp. nov. is abundant. This species is characterized by a short stem, which is unusual for this genus. In situ immature microspores and megaspores were found in some specimens. Lepacyclotes bechstaedtii sp. nov. has a quadrilobe corm with fertile scales inserted in whorls or slightly helicoidally. Short sterile leaves arise distally from the corm in some specimens. Selaginellales are very rare in the flora; Selaginellites leonardii sp. nov. is represented by a strobilus that yielded both micro‐ and megaspores. Some sterile fragments have been found associated, but never in organic connection.     

What do we know about Hawaiian ferns and lycophytes?

The Hawaiian Islands are home to one of the most distinctive fern and lycophyte floras in the world. Of the 144 native fern species, 76% are endemic and, including subspecies and varieties, 84% of the 167 native fern taxa are endemic. There are 15 native lycophyte species, 47% of which are endemic, and 16 taxa, 50% of which are endemic. I review here most of the available literature on Hawaiian ferns and lycophytes. Few species of ferns or lycophytes have been studied in any kind of detail and, for most, we only know basic classification and general ecological information. Although the total number of studies reviewed here is not large, research has been conducted on a wide range of topics including systematics, floristics, dispersal, phylogeny, biogeography, ecology, form and function, population genetics, microevolution, fern-animal and fern-fungi associations, reproductive biology, demography, ethnobotany, and conservation.     

A large‐scale phylogeny of the lycophyte genus Selaginella (Selaginellaceae: Lycopodiopsida) based on plastid and nuclear loci

The lycophyte genus Selaginella alone constitutes the family Selaginellaceae, the largest of the lycophyte families. The genus is estimated to contain 700–800 species distributed on all continents except Antarctica, with highest species diversity in tropical and subtropical regions. The monophyly of Selaginella in this broad sense has rarely been doubted, whereas its intrageneric classification has been notoriously contentious. Previous molecular studies were based on very sparse sampling of Selaginella (up to 62 species) and often used DNA sequence data from one genome. In the present study, DNA sequences of one plastid (rbcL) and one nuclear (ITS) locus from 394 accessions representing approximately 200 species of Selaginella worldwide were used to infer a phylogeny using maximum likelihood, Bayesian inference and maximum parsimony methods. The study identifies strongly supported major clades and well resolves relationships among them. Major results include: (i) six deep‐level clades are discovered representing the deep splits of Selaginella; and (ii) 20 major clades representing 20 major evolutionary lineages are identified, which differ from one another in molecular, macro‐morphological, ecological and spore features, and/or geographical distribution.     

Morphological Comparisons Between Xiphinema rivesi Daimasso and X. americanum Cobb Populations from the Eastern United States

Though in the past Xiphinema americanum has been the most commonly reported dagger nematode in the eastern United States, our studies revealed the presence in Pennsvlvania of a previously unrecognized and unreported species related to X. americanum, Morphometric data and photomicrographs establish the identity of this form as X. rivesi and show expected variations in populations of this species from various locations. Similar data and illustrations are given for X. americanum populations from Pennsylvania and other areas, showing variations and relationships. Xiphinema rivesi is widely distributed in the fruit producing area of south-central Pennsylvania and is also reported herein from raspberry in Vermont and apple in Maryland and New York. This species is frequently found in fruit growing areas of Pennsylvania associated with tomato ringspot virus-induced diseases and is also found associated with corn, bluegrass sod, and alfalfa.     

A new species of Phoenicopsis (Leptostrobales) from the Maastrichtian–Danian of Chukotka,Russia

A new species, Phoenicopsis anadyrensis Nosova, is described based on the leaf morphology and cuticle features from the Maastrichtian–Danian Rarytkin Formation, Chukotka, North-East of Russia. It is characterized by hypostomatic leaves with stomatal bands on the abaxial side, undulate anticlinal epidermal cell walls and papillae on the epidermal cells and on the subsidiary cells of the stomata. The new species is the youngest reliable representative of the genus Phoenicopsis. This record extends the stratigraphic range of Phoenicopsis from its previously known latest records in the early Campanian up to Maastrichtian–Danian. The persistence of the genus Phoenicopsis up to the Cretaceous–Paleogene boundary is most likely related with vicinity to mountain floras associated with Late Cretaceous and Paleogene volcanic uplands.     

C. S. Sargent’s crataegus (Rosaceae) types from western Pennsylvania

A large amount of unmounted material ofCrataegus (Rosaceae) at Carnegie Museum (CM) was studied and found to include types of species described by C. S. Sargent from western Pennsylvania. These are of interest because Sargent'sCrataegus types were previously thought to be only at the Arnold Arboretum (A). Sargent's method of choosing types (designating a living “type tree” and citing several specimens collected from it) is discussed and clarified.Crataegus types at A were compared with the material at CM. An annotated list of the western Pennsylvania types in both herbaria is presented.     

Root evolution at the base of the lycophyte clade: insights from an Early Devonian lycophyte

Background and Aims The evolution of complex rooting systems during the Devonian had significant impacts on global terrestrial ecosystems and the evolution of plant body plans. However, detailed understanding of the pathways of root evolution and the architecture of early rooting systems is currently lacking. We describe the architecture and resolve the structural homology of the rooting system of an Early Devonian basal lycophyte. Insights gained from these fossils are used to address lycophyte root evolution and homology.Methods Plant fossils are preserved as carbonaceous compressions at Cottonwood Canyon (Wyoming), in the Lochkovian–Pragian (∼411 Ma; Early Devonian) Beartooth Butte Formation. We analysed 177 rock specimens and documented morphology, cuticular anatomy and structural relationships, as well as stratigraphic position and taphonomic conditions.Key Results The rooting system of the Cottonwood Canyon lycophyte is composed of modified stems that bear fine, dichotomously branching lateral roots. These modified stems, referred to as root-bearing axes, are produced at branching points of the above-ground shoot system. Root-bearing axes preserved in growth position exhibit evidence of positive gravitropism, whereas the lateral roots extend horizontally. Consistent recurrence of these features in successive populations of the plant preserved in situ demonstrates that they represent constitutive structural traits and not opportunistic responses of a flexible developmental programme.Conclusions This is the oldest direct evidence for a rooting system preserved in growth position. These rooting systems, which can be traced to a parent plant, include some of the earliest roots known to date and demonstrate that substantial plant–substrate interactions were under way by Early Devonian time. The morphological relationships between stems, root-bearing axes and roots corroborate evidence that positive gravitropism and root identity were evolutionarily uncoupled in lycophytes, and challenge the hypothesis that roots evolved from branches of the above-ground axial system, suggesting instead that lycophyte roots arose as a novel organ.     

Late Cretaceous Arman Flora of the Magadan District: Composition, age, and new plant species

The Arman Flora comes from volcanic-sedimentary deposits of the Arman Formation in the Arman River basin and from volcanic and volcanic-sedimentary rocks of the Nel??kandzha-Khasyn Interfluve. It comprises about 80 fossil plant species. The Arman Flora is dated as Turonian and Coniacian because of its similarity to the reliably dated Penzhina and Kaivayam floras of the northwestern Kamchatka Peninsula and Tylpegyrgynai Flora of the Pekul??nei Ridge. This is corroborated by isotopic (U-Pb and ⁴⁰Ar/³⁹Ar) age determination for the plant-bearing layers. New conifer and angiosperm species of the Arman Flora are described: Pagiophyllum parvum sp. nov., Araliaephyllum armanensis sp. nov., Terechovia philippovae sp. nov., and Parvileguminophyllum samylinae sp. nov.     

Seasonal Population Fluctuation of Xiphinema americanum and X. rivesi in New York and Pennsylvania Orchards

The population fluctuation and composition of Xiphinema americanum (sensu stricto) and X. rivesi were studied in a New York apple orchard (only X. americanum present), a Pennsylvania apple orchard (both X. americanum and X. rivesi present), and a Pennsylvania peach orchard (X. americanum, X. rivesi, and X. californicum present). Few clear trends in population fluctuation or composition were observed. The adult female was the predominant stage in most sample periods, and the reproductive period was limited to late spring and early summer. Only a few of the females at any sample period were gravid. All stages were present throughout the year, and all stages overwintered. Eggs in soil were not monitored. In the Pennsylvania apple orchard, X. americanum and X. rivesi were easily separated by morphological characteristics; however, the two species did not display differences in population structure or composition. The predominance of adults, the relatively low reproductive rates, and the association of these species with stable habitats suggest that the life strategies of X. americanum and X. rivesi are K-selected as opposed to r-selected.