Studies of protonemal morphogenesis in mosses. X. Ephemeraceae revisited; new dimensions underground

Abstract

This systematic investigation of the filament systems in nine species of Ephemerum and two of Micromitrium revealed a range of new characters in the Ephemeraceae. Above ground most taxa have pointed chloronemata with widely spreading branches, whereas in Micromitrium, Ephemerum cohaerens and E. spinulosum, the branches are fastigiated. Four species of Ephemerum (E. sessile, E. cohaerens, E. spinulosum and E. hibernicum) have massive lipid-laden tubers, the last three with prominent spinulose side branches. Tubers, comprising chains of rounded cells, are described for the first time in Micromitrium. Unique to E. recurvifolium are starch-laden tubers and fragile chloronemal branches. The morphology of the diaspores reinforces the pottialean affinities of the Ephemeraceae. The production of long-lived tubers provides Ephemerum species predominantly found on lake and reservoir margins in the British Isles, with an alternative means of perennation on sites susceptible to inundation prior to sporophyte maturation.     

Notes on taxonomy of some European species of Ephemerum (Bryopsida: Pottiaceae)

Abstract

Taxonomy of some European species of Ephemerum is reviewed. As in several other recent studies, E. minutissimum Lindb. is regarded as a distinct species from E. serratum (Hedw.) Hampe; it is recorded from N. America (by the newly designated lectotype and other specimens) and Turkey, in addition to Europe. E. serratum var. angustifolium Bruch & Schimp. may be a synonym of E. minutissimum; the costate forms E. serratum var. praecox A.W.H.Walther & Molendo and E. intermedium Mitt. in Braithw. are treated as synonyms of E. serratum s.str. Type specimens of E. stellatum H.Philib. are described, a lectotype is designated and it is placed as a synonym of E. serratum s.str. E. hibernicum Holyoak & V.S.Bryan is regarded as a synonym of E. rutheanum Schimp. in Ruthe. The latter is shown to be a rare, European endemic taxon with modern records from Ireland, S. Wales, Germany and The Netherlands, and old records from France and W. Poland; a lectotype is designated. Forms intermediate between E. sessile (Bruch.) Müll.Hal. and the N. American E. crassinervium (Schwägr.) Hampe occur in several countries in W. Europe, some of them indistinguishable from some of the American plants; forms intermediate between E. sessile and E. rutheanum are recorded from S. Portugal and (rarely) Ireland. Differences between E. crassinervium, E. sessile and E. rutheanum in characters of leaves, tubers and capsules are shown to be slight, with considerable overlap. Hence all three taxa are treated as subspecies of E. crassinervium. A revised key to European Ephemerum and Micromitrium is presented.     

Sequencing type material resolves the identity and distribution of the generitype Lithophyllum incrustans,and related European species L. hibernicum and L. bathyporum (Corallinales,Rhodophyta)

DNA sequences from type material in the nongeniculate coralline genus Lithophyllum were used to unambiguously link some European species names to field‐collected specimens, thus providing a great advance over morpho‐anatomical identifi‐cation. In particular, sequence comparisons of rbcL, COI and psbA genes from field‐collected specimens allowed the following conclusion: the generitype species, L. incrustans, occurs mostly as subtidal rhodoliths and crusts on both Atlantic and Mediterranean coasts, and not as the common, NE Atlantic, epilithic, intertidal crust reported in the literature. The heterotypic type material of L. hibernicum was narrowed to one rhodolith belonging in Lithophyllum. As well as occurring as a subtidal rhodolith, L. hibernicum is a common, epilithic and epizoic crust in the intertidal zone from Ireland south to Mediterranean France. A set of four features distinguished L. incrustans from L. hibernicum, including epithallial cell diameter, pore canal shape of sporangial conceptacles and sporangium height and diameter. An rbcL sequence of the lectotype of Lithophyllum bathyporum, which was recently proposed to accommodate Atlantic intertidal collections of L. incrustans, corresponded to a distinct taxon hitherto known only from Brittany as the subtidal, bisporangial, lectotype, but also occurs intertidally in Atlantic Spain. Specimens from Ireland and France morpho‐anatomically identified as L. fasciculatum and a specimen from Cornwall likewise identified as L. duckerae were resolved as L. incrustans and L. hibernicum, respectively.     

Plagiochila britannica,a new species in the British Isles

Abstract

Plagiochila britannica is described as a new species. It differs from P. porelloides and P. asplenioides in many characters, especially its often more narrowly oval leaves with a more variable, often truncate to bilobed apex and larger cells, its wider antical stem cells and its diploid chromosome number. Differences from P. arctica var intermedia include its more variable leaf apex, generally more dentate leaves often with longer teeth, the greater maximum size of its leaf cells and its wider antical stem cells. Male and female inflorescences and sporophytes are known in P. britannica, which favours base-rich substrata and has been found in Wales, N. England, Scotland and N. Ireland. A key to the nine species of Plagiochila in the British Isles is included.     

Bryophyte flora of Uganda. 3. Lophoziaceae

Abstract

We studied infraspecific morphological variation within European Dicranum majus Sm. A principal components analysis based on six leaf characters scored in 82 specimens revealed two distinct plant types. Plants with bistratose submarginal upper leaf lamina cells, numerous spine-like dorsal lamina projections, a costa that is dorsally rough far down and has two layers of guide cells in its basal part, and falcate or strongly falcate, long leaves are mainly of a relatively southern origin. Specimens with a unistratose, smooth upper leaf lamina, a costa that is dorsally rough only above and has one layer of guide cells, and with slightly curved to straight, short leaves were only collected in northern Europe. Even if most authors do not formally recognize variation within D. majus, our results suggest that the two kinds of plants should be recognized at least at the variety level. In view of the confusing nomenclature in Dicranum it is beyond the scope of this paper to find a name for the northern plant. Type material of D. majus var. orthophyllum A. Braun ex Milde, a name that was frequently used for northern North American plants, belongs to the southern phenotype.     

Auxin‐mediated lamina growth in tomato leaves is restricted by two parallel mechanisms

In the development of tomato compound leaves, local auxin maxima points, separated by the expression of the Aux/IAA protein SlIAA9/ENTIRE (E), direct the formation of discrete leaflets along the leaf margin. The local auxin maxima promote leaflet initiation, while E acts between leaflets to inhibit auxin response and lamina growth, enabling leaflet separation. Here, we show that a group of auxin response factors (ARFs), which are targeted by miR160, antagonizes auxin response and lamina growth in conjunction with E. In wild‐type leaf primordia, the miR160‐targeted ARFs SlARF10A and SlARF17 are expressed in leaflets, and SlmiR160 is expressed in provascular tissues. Leaf overexpression of the miR160‐targeted ARFs SlARF10A, SlARF10B or SlARF17, led to reduced lamina and increased leaf complexity, and suppressed auxin response in young leaves. In agreement, leaf overexpression of miR160 resulted in simplified leaves due to ectopic lamina growth between leaflets, reminiscent of e leaves. Genetic interactions suggest that E and miR160‐targeted ARFs act partially redundantly but are both required for local inhibition of lamina growth between initiating leaflets. These results show that different types of auxin signal antagonists act cooperatively to ensure leaflet separation in tomato leaf margins.     

Four new species of Adenocalymma (Bignoniaceae) and a key to the species from southeastern Brazil

Four new species of Adenocalymma (Bignoniaceae, Bignonieae) from southeastern Brazil are described and illustrated: A. aurantiacum, characterized by dark orange and infundibuliform corolla; A. cinereum, characterized by shrubby habit, greyish inflorescence, infundibuliform corolla, and exserted stamens; A. gibbosum, characterized by gibbous and orange corolla and an inflorescence with dendritic trichomes; and A. sessile, characterized by sessile leaves and gibbous corolla. A discussion on the relationships of the new taxa and a key to all 29 species of Adenocalymma reported from southeastern Brazil are provided.     

Two new mosses from Tanzania

Abstract

Weissia brachypoma sp. nov. and Ephemerum pemzinutum sp. nov. are described from western Tanzania.     

Some additions to the bryophyte flora of the Azores

Abstract

This paper lists the noteworthy bryophytes collected by the authors in 1980 and 1992 on five of the nine islands of the Azores. Twenty-one species are new to the Azores three of these (Riccia beyrichiana, Dicranella schreberiana and Ephemerum cohaerens) being new to Macaronesia. Reasons are given for regarding Ptychomitrium azoricum as a synonym of P. polyphyllum and Tortella cirrifolia as a variety or subspecies of T. nitida.     

A multivariate approach to identify vegetation belts: Gallery forest and its surrounding savanna along the river Kota in north Benin

Abstract

The floristic composition and spatial structure of a West African riverine forest in north-western Benin were studied in order to identify vegetation zones and their arrangement and composition. Data were collected on five continuous belt transects and were analysed using multivariate methods. A total of 133 tree taxa from 34 plant families were identified, with Rubiaceae and Leguminosae-Papilionoideae as the most frequent families. Fifteen homogeneous transect sections were documented. Near-river sections were dominated by water-demanding species (Syzygium guineense, Garcinia ovalifolia, Berlinia grandiflora, Breonardia salicina) (=gallery forest), whereas uphill sections were characterised by savanna species (Terminalia laxiflora, Hymenocardia acida, Detarium microcarpum, Burkea africana) (= savanna). The shift from gallery forest to savanna was reflected by a floristic turnover and the different physiognomy of the vegetation, although diversity values for gallery forest and savanna were very similar. In the Principal Co-ordinates Analysis (PCoA), gallery forest and savanna sections did not overlap. Parallel sections at both sides of the river could be linked by isolines following the topography parallel to the river, resulting in a continuous gallery forest belt (width between 10 and 30 m) flanked by savanna. Tree species typical for gallery forests have wider areas of distribution than savanna species.     

Eimeria and Klossia spp. (Protozoa: Sporozoa) from Wild Mammals in Borneo*

SYNOPSIS. During a survey of parasites of Sabah mammals, coccidia oocysts were found in 9 of 22 host species examined. Sporulated oocysts of Klossia sp. from Rattus whiteheadi are described. New geographic records are reported for Eimeria callosciuri, Eimeria sabani, and Eimeria tupaiae. New host and geographic records are reported for Eimeria separata from Rattus cremoriventer, for E. tupaiae and Eimeria ferruginea from Tupaia tana, for Eimeria nieschulzi from Rattus muelleri, and for E. sabani and Klossia sp. from R. whiteheadi.     

SOME ASPECTS OF THE ECOLOGY OF THE FRESHWATER CRAB (POTAMONAUTES PERLATUS MILNE EDWARDS) IN THE UPPER REACHES OF THE BUFFALO RIVER,EASTERN CAPE PROVINCE,SOUTH AFRICA.

Summary

Freshwater crabs (Potamonautes perlatus) are the largest naturally occurring invertebrates in southern African rivers. The ecology of these animals in South African riverine ecosystems is little understood. This study investigates some aspects of the population and feeding ecology of P. perlatus in the upper reaches of the Buffalo River. The densities of crabs (carapace width larger than 25 mm) at two sites in the river ranged between 1.72 and 5.25 crabs m², higher than previously recorded for freshwater crabs in rivers in southern Africa and southern Italy. Twenty-four hour observations revealed that P. perlatus has a nocturnal habit. The diet of P. perlatus was established by examination of the contents of the fore-gut. Crabs with a carapace width smaller than 40 mm fed predominantly on aquatic invertebrates while larger crabs fed on allochthanous material (leaf litter), detritus and algae. Through feeding, crabs reduced the surface area of leaves in the stream by 99.95%.     

Comparison of the Giemsa C-banded and N-banded karyotypes of twoElymus species,E. dentatus andE. glaucescens (Poaceae: Triticeae)

The karyotypes ofElymus dentatus from Kashmir andE. glaucescens from Tierra del Fuego, both carrying genomesS andH, were investigated by C- and N-banding. Both taxa had 2n = 4x = 28. The karyotype ofE. dentatus was symmetrical with large chromosomes. It had 18 metacentric, four submetacentric and six satellited chromosomes. The karyotype ofE. glaucescens resembled that ofE. dentatus, but a satellited chromosome pair was replaced by a morphologically similar, non-satellited pair. The C-banding patterns of both species had from one to five conspicuous and a few inconspicuous bands per chromosome. N-banding differentiated the chromosomes of the constituent genomes by producing bands in theH genome only. TheS genomes of both species were similar with five metacentric and two satellited chromosomes having most conspicuous C-bands at telomeric and distal positions. They resembled theS genome of the genusPseudoroegneria. TheH genomes had four similar metacentric and two submetacentric chromosomes. The seventhH genome chromosome ofE. dentatus was satellited, that ofE. glaucescens nonsatellited, but otherwise morphologically similar. The C-bands were distributed at no preferential positions. TheH genome ofE. dentatus resembles theH genomes of some diploidHordeum taxa.     

The cultivation of mosses and liverworts

Abstract

Rhynchostegium confusum, a new species from Spain and the Iberian Peninsula is described. It is closely related to R. confertum, from which it differs in its noticeably wider stem leaves with wider and apically spurred costa, more flexuous branch leaves, and shorter seta. It also differs in its habit and habitat: the plants are tightly attached to siliceous rocks just over the water level in rivulets that dry out during the summer in the Mediterranean region. Molecular data show that the new species derives from R. confertum, but is clearly differentiated from the studied populations of the latter in a number of missing haplotypes.     

Leaf growth characteristics of Vitis vinifera and prediction of final lamina length for studies of powdery mildew

Total functional leaf area is a key factor in determining crop yield. A nonlinear mixed‐effects model was employed to estimate growth responses for individual leaves using repeated measures of lamina length ≥30 mm, in the absence of disease. Resulting growth curves make allowances for, and allow assessment of, leaf to leaf variability. The major source of variability in leaf growth was identified as differences in thermal time required to reach half final lamina length. Juvenile leaves of Vitis vinifera are susceptible to infection by the powdery mildew fungus (Erysiphe necator) which impairs leaf function. The model was used to predict unobserved final lamina length for a subset of leaves inoculated with E. necator immediately after observations ceased. The severity of infection by E. necator varies among infected leaves. A previous study identified which of the inoculated leaves developed symptoms of severe powdery mildew. Maximum severity of infection was found to occur when individual leaves were at 85.3–97.9% of predicted final lamina length.     

A new species of Eremogone (Caryophyllaceae) from northern Utah and southeastern Idaho, U.S.A.

A name (Eremogone loisiae) is provided for those plants from northern Utah and southeastern Idaho that have gone under the misapplied name Eremogone kingii subsp. uintahensis. Eremogone loisiae, named in honor of Lois A. Arnow, is distinguished from E. kingii by its longer and narrower, flexuous leaves and its longer sepals, petals, styles, capsules, and seeds.     

Extended-spectrum beta-lactamase-producing Escherichia coli harbouring sul and mcr-1 genes isolates from fish gut contents in the Mekong Delta,Vietnam

This study investigated the existence of sulfonamides and colistin resistance genes among extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli recovered from fish gut in Vietnam and evaluated the susceptibility patterns of the ESBL-producing E. coli to relevant antimicrobials. A total of 88 ESBL-producing E. coli isolates were analysed for the presence of the ESBLs, sul (1, 2, 3) and mcr (1–3) genes by PCR. Antimicrobial resistance phenotypes of isolates were determined by disc diffusion. Results showed that: (i) A high prevalence of 94·3% of sulfonamide resistance was observed in 88 isolates. Moreover, the existence of 2·3% of ESBL-producing E. coli harbouring mcr-1 gene were detected; (ii) The phylogenetic types A and B1 were most frequent, and the bla_CTX-M group1 and bla_TEM genes encoding ESBL were detected in 47·7% of the isolates; (iii) ESBL-producing E. coli harbouring mcr-1 gene exhibited resistance to 11 antibiotics. The existence of mcr-1 and sul1,2,3 genes and the extremely high level of multiple drug resistance in all ESBL-producing E. coli isolates obtained from sampled fish in Vietnam is a major concern. Therefore, it is imperative to monitor ESBL-producing E. coli in the river waters of Vietnam.     

Extreme life history plasticity and the evolution of invasive characteristics in a native ant

Disturbance resulting from urbanization is a leading cause of biotic homogenization worldwide. Native species are replaced with widespread non-native species and ants are among the world’s most notorious invaders. To date, all documented cases of ant invasions involve exotic introduced species that are spread around the world by human-mediated dispersal. I investigated the effect of urbanization on the evolution of invasive characteristics in a native ant species, the odorous house ant, Tapinoma sessile (Say). Colony social structure, life history traits, and the spatial pattern of nest distribution were compared by sampling T. sessile across a gradient of three distinct habitats: natural, semi-natural, and urban. Results demonstrate a remarkable transition in colony social and spatial structure and life history traits between natural and urban environments. In natural habitats, T. sessile colonies are comprised of small, monogyne (single queen), and monodomous (single nest) colonies. In urban areas, T. sessile often exhibit extreme polygyny and polydomy, form large supercolonies, and become a dominant pest. Results also suggest that urban T. sessile colonies may have a negative impact on native ant abundance and diversity. In the natural environment T. sessile coexisted with a wide array of other ant species, while very few ant species were present in the urban environment invaded by T. sessile. Habitat degradation and urbanization can lead to extreme changes in social and spatial colony structure and life history traits in a native ant species and can promote the evolution of invasive characteristics such as polygyny, polydomy, and supercolonial colony structure.     

On the taxonomic position of Sciaromium lacustre Herz. & Rich. in Rich.

Abstract

Sciaromium lacustre Herz. & Rich. in Rich. from Peru is misplaced in Sciaromium and a new genus, Richardsiopsis, is erected to accommodate it. Richardsiopsis is considered most closely related to Donrichardsia macroneuron (Grout) Crum & Anderson from Texas on the basis of their similar gametophyte characters including the strong costa, oblong-rhomboidal to linear-flexuose, prorate lamina cells which are partly arranged in pluristratose strands and foliose, suborbicular, broadly rounded at the apex pseudoparaphyllia.