Freshwater ascomycetes: Wicklowia aquatica, a new genus and species in the Pleosporales from Florida and Costa Rica

During a latitudinal survey of freshwater ascomycetes, an unidentified fungus with bitunicate asci was found on submerged wood and herbaceous material from Florida and Costa Rica. Based on morphological characteristics and 28S rDNA large subunit (LSU) sequence data, this fungus is described as a new genus and species, Wicklowia aquatica, and placed in the Pleosporales (Pleosporomycetidae, Dothideomycetes). Phylogenetic analyses based on LSU sequences did not resolve the familial placement of W. aquatica within the Pleosporales. The characteristic features of W. aquatica are subglobose, dorsiventrally flattened, ostiolate, immersed to erumpent, black ascomata; a peridial wall composed of 4–5 layers of darkened pseudoparenchymatic cells; cellular pseudoparaphyses immersed in a gel matrix; broadly clavate, bitunicate asci; and cylindrical, hyaline, one-septate ascospores with rounded apices and surrounded by a gelatinous sheath that expands in water; ascospore sheath attached at the ascospore base with a gelatinous curtain extending from the base that fragments into basal filamentous appendages which radiate from the base of the ascospore.     

Four new species and a new Chinese record of the nectrioid fungi

Four new species belonging to Bionectria, Calonectria, Haematonectria and Neonectria on plant substrates collected from nature reserves in southern and central China are described. Bionectria truncata has smooth perithecia of a flattened to shallow discoid apex, clavate asci with an apical ring, and ellipsoid, smooth to spinulose ascospores. Calonectria dicephalospora is characterized by pyriform perithecia with a warted surface, clavate asci with a simple apex and long, narrow stalk, and fusoid ascospores with a cap-like appendage at each end. Haematonectria lushanensis possesses warted perithecia which are laterally collapsing when dry, cylindrical asci with a simple apex, and ellipsoid, spinulose ascospores. Neonectria dinghushanica is distinguishable by subglobose perithecia with a warted surface, clavate asci, and striate ascospores. Morphological features of these new species are described comprehensively and compared with their related fungi. Neonectria castaneicola is recorded as new to China.     

ADDITIONAL SPECIES OF PODODIMERIA (LOCULOASCOMYCETES)

Pododimeria, containing the brown-spored species P. gallica and P. andina, is expanded to include species with hyaline as well as brown ascospores. Two new hyalodidymous taxa, P. juniperi and P. gelatinosa, are added to the genus. Species of Pododimeria occur as ectocommensals on living shoots of Cupressaceae or Podocarpaceae. Although the superficial mycelium may extend into the labyrinthine chambers enclosed by the imbricated scale leaves of the host, it does not penetrate the cuticle. The tiny, black, subglobose, uniloculate ascocarps taper basally to stromatic stipes. The bitunicate asci are interspersed with pseudoparaphyses composed of broad, irregularly shaped cells that readily break apart. The thick, brown to bluish-green ascocarp wall of P. juniperi has a broad equatorial band of prosenchymatous cells. The ascocarp wall of P. gelatinosa is composed uniformly of subhyaline, gelatinous pseudoparenchymatous cells covered by a dark, amorphous crust.     

Dyrithiopsis lakefuxianensis gen. et sp. nov. from Fuxian Lake, Yunnan, China, and notes on the taxonomic confusion surrounding Dyrithium

A new taxon with Dyrithium-like characteristics was collected from Lake Fuxian in China. The taxon is typical of the Amphisphaeriaceae in that it has relatively large, ostiolate, immersed ascomata, unitunicate asci with a J+ subapical ring, and brown ascospores. It is similar to Dyrithium in that it has muriform ascospores, but considerable confusion surrounds this genus. In Dyrithium asci are bitunicate and lack a J+ subapical ring, while this was not true of our species. A new genus, Dyrithiopsis, therefore is established to accommodate this new taxon. Details of its anamorph also are provided, based on cultural studies. Parsimony analyses of part of the large-subunit rDNA provide further evidence to support the familial placement of this new genus in the Amphisphaeriaceae. The taxonomic position of Dyrithium also is discussed.     

ULTRASTRUCTURE OF ASCOCARP DEVELOPMENT IN SPORORMIA AUSTRALIS

Thin sections taken from intact ascocarps were examined to trace the developmental sequence of ascocarp formation in Sporormia australis Speg. The ascocarp originated from a uninucleate vegetative hyphal cell which underwent repeated divisions and formed an ascostroma. In the center of the young ascostroma a cavity formed, apparently from cell disintegrations, and enlarged as the ascocarp enlarged. Within the cavity pseudoparaphyses developed from undifferentiated pseudoparenchymatous cells at the apex of the cavity and extended downward. Ascogenous hyphae arose from proliferating uninucleate cells at the base of the cavity. As the ascocarp matured, the pseudoparenchymatous cells differentiated into three layers, none of which were considered homologous to the perithecial wall lining the cavity of pyrenomycetes. The cells of the apex were not differentiated into layers and light microscopy revealed the presence of an ostiole through which bitunicate asci discharged their eight 4-celled ascospores.     

MORPHOLOGY OF TRICHOMETASPHAERIA TURCICA

Ascocarps of Trichometasphaeria turcica Luttrell originated in culture as globose parenchymatous stromata within which ascogonia differentiated. As the ascostroma enlarged, stromal cells immediately above the ascogonium produced hyphal outgrowths whose tips grew downward and intertwined beneath the ascogonium. Intercalary growth of these hyphae formed a pseudoparaphysate centrum. Ascogenous hyphae near the base of the centrum produced bitunicate asci which grew upward among the persistent pseudoparaphyses. The ostiole was a broad pore resulting from dissolution of the peripheral stromal cells above the apex of the single locule. Spiny outgrowths from the peripheral cells surrounded the ostiole. The bitunicate asci and ascostromatic ascocarps place this fungus in the subclass Loculoascomycetidae. The pseudoparaphysate centrum and perithecioid ascostroma are characteristic of the Pleosporales. The apparently insignificant character of a protruding conidial hilum was the only essential feature distinguishing Helminthosporium turcicum Pass., the conidial stage of T. turcica, from H. maydis Nisik. & Miyake, a typical representative of species of Helminthosporium with perfect stages in Cochliobolus.     

Arecophila bambusae sp. nov. andA. coronata comb. nov., from dead culms of bamboo

A new species ofArecophila and a species previously known asAmphisphaeria coronata are described and illustrated from dead culms of bamboo.Arecophila bambusae sp. nov. is distinct in the genus in having ellipsoidal ascospores with slightly round ends, and asci with a narrow subapical ring.Arecophila coronata comb. nov. has asci with a wedgeshaped apical ring and weakly striated ascospores enclosed in wide mucilaginous sheath.     

New species of <Emphasis Type="Italic">Clohiesia</Emphasis> and <Emphasis Type="Italic">Paraniesslia</Emphasis> collected from freshwater habitats in China

Two fungi collected from submerged woody debris were found to represent hitherto undescribed species of the ascomycete genera Clohiesia and Paraniesslia. They are described as Clohiesia curvispora sp. nov. and Paraniesslia aquatica sp. nov. based on morphological characters. Clohiesia curvispora is characterized by immersed ascomata under a clypeus, and unitunicate, cylindrical asci containing one-celled, curved, elongate-fusiform ascospores. Paraniesslia aquatica is characterized by small, superficial, setose ascomata, and unitunicate, clavate asci containing verrucose, brown ascospores. Each species is illustrated with light micrographs and compared with similar taxa in this article.     

Two new species ofHeleococcum withAcremonium anamorphs

Two new species ofHeleococcum (a cleistothecial nectrioid genus in the Hypocreaceae) are described and illustrated.Heleococcum alatosporum, isolated from Indonesian soil, is recognized by the production of salmon-colored ascomata, cylindrical asci, and hyaline, small, bicellular ascospores with walls that are verruculose and ornamented with longitudinal ridges.Heleococcum inapertum, isolated from Philippine soil, is characterized by yellow ascomata, clavate asci, and pale yellow, middle-sized, bicellular, verruculose to weakly striate ascospores surrounded with a hyaline sheath. Anamorphs of the new species are included inAcremonium. A key to the accepted species of the genus is provided.     

A new species ofClohiesia from Hong Kong

Clohiesia lignicola sp. nov. (freshwater ascomycetes) is introduced based on a specimen collected on submerged wood in the Tung Chung River, Hong Kong. Ascomata are clypeate, asci are cylindric-clavate with a relatively massive apical apparatus and ascospores are fusoid-ellipsoidal.Clohiesia lignicola differs fromC. corticola in having wider asci and wider fusoid-ellipsoidal ascospores, and larger ascomata.Clohiesia lignicola is described and illustrated with light micrographs and is also compared with species in the genus,Annulatascus.     

Two new species ofConiochaeta with a cephalothecoid peridium wall

Two new species ofConiochaeta, isolated from Japanese soils, are described and illustrated:C. cephalothecoides, which is characterized by dark brown ascomata clothed with short setae, cylindrical asci and ovoid to almond-shaped or pyriform ascospores with a longitudinal germ slit; andC. dumosa, which is characterized by dark brown ascomata clothed with short setae and dense hyphal hairs, cylindrical asci and ellipsoid-fusoid ascospores with a longitudinal germ slit. These species are distinguished from most species of the genus by the unique cephalothecoid peridium of their ascomata. The associated anamorphs of both species are assignable to the form-genusLecythophora.     

EFFECT OF CARBON AND NITROGEN NUTRITION ON REPRODUCTION IN LEPTOSPHAERULINA BRIOSIANA

Reproduction of Leptosphaerulina briosiana was studied on modified Richard's medium supplemented with seven carbon compounds, six amino acids, five inorganic nitrogen compounds or with urea. The fungus grew on each of the media, but it did not reproduce on all. Ascostromata formed on each of the carbon sources, but the formation of asci and ascospores and the ejection of ascospores varied with the carbon source and the isolate of the fungus. Ascostromata formed on all the nitrogen sources except arginine and ammonium sulfate. Formation of asci and ascospores and ejection of the ascospores varied with the nitrogen source and the isolate of the fungus. The fungus grew and produced ascostromata on Richard's medium supplemented with each of six vitamins, but asci and ascospores were not formed.     

New species of <Emphasis Type="Italic">Moristroma</Emphasis> (Ascomycetes) and phylogenetic position of the genus

The loculoascomycete Moristroma quercinum sp. nov. and Moristroma japonicum sp. nov. are described from Northern Europe (Denmark, Lithuania, Sweden) and Japan, respectively. M. quercinum is reported from wood of Quercus robur and Q. petraea, and M. japonicum is reported from wood of Quercus mongolica var. grossoserrata. Ascostromata of both species were found on hard heartwood of attached or shed branches. The two new species differ from the type species of the genus, M. polysporum, by the presence of pycnidia, and by the size of ascostromata, asci and ascospores. Drawings illustrate ascostromata, pycnidia, asci, hamathecium and ascospores of the two new species. A phylogenetic analysis suggests that Moristroma belongs to the Chaetothyriomycetes, rather than to the Dothideomycetes as previously suggested.     

Venturia chinensis sp. nov., a new venturialean ascomycete from Khingan Mountains

A new species of Venturia (V. chinensis) is described and illustrated from the leaves of Lonicera praeflorens collected from Lesser Khingan Mountains, the northeast China. It is characterized by habitat saprobic; ascomata small-sized, solitary or scattered, superficial, subglobose to citriform, wall black, papillate, ostiolate, covered with setae; peridium thin; hamathecium evanescent in mature ascomata; asci 8-spored, bitunicate, fissitunicate, oblong to obclavate, with or without a short, knob-like pedicel; ascospores ellipsoidal, olivaceous pale brown, 1-septate, ascospore wall thin, smooth. Comparisons of V. chinensis with V. lonicerae (another species on Lonicera caerulea) and other species of Venturia lead to the conclusion that collected taxon is new. Its relationships with other species of Venturia are discussed based on morphology and 28S nrDNA and ITS nrDNA sequence comparisons.     

Morphology,development and cytology of Taphrina maculans Butler

Morphology, development and nuclear behavior of the ascogenous stroma and asci in the infection spots have been described inTaphrina maculans Butler. The fungus forms subcuticular and intercellular mycelium in the leaf tissues and the ascogenous layers originate through division of the subcuticular hyphal cells in the infection sites. Germination of ascogenous cells starts with their elongation in the uppermost layer forming asci and ascospores without formation of stalk cells. Meiosis of the fusion (diploid) nucleus occurs in the young ascus as in otherTaphrina species devoid of stalk cells. The haploid chromosome complement in this species consists of 3 chromosomes (n=3). All the cells in the stromatic layer are potential ascogenous cells and ascus formation continues, until all of them are exhausted in the infection spot. Eight ascospores are normally formed in each ascus, but multi-plication of ascospores may occurin situ later. Three morphologically distinct types of ascus opening are encountered, which are apparently not correlated with prevalent environment. Multiplication of ascospores after their discharge from mature asci occurs by budding proceded by a mitotic division of the spore nucleus. Blastospores (budded cells) germinate into short hyphae and binucleate condition of cells originates by mitotic division of the nucleus. Occurrence of giant cells containing 2 nuclei is often observed. Possible origin of Uredinales fromTaphrina-like ancestors has been indicated due to their close resemblance.     

Oxylipin covered ascospores of Eremothecium coryli

Eremothecium coryli is known to produce intriguing spindle-shaped ascospores with long and thin whip-like appendages. Here, ultra structural studies using scanning electron microscopy, indicate that these appendages serve to coil around themselves and around ascospores causing spore aggregation. Furthermore, using immunofluorescence confocal laser scanning microscopy it was found that hydrophobic 3-hydroxy oxylipins cover the surfaces of these ascospores. Using gas chromatography–mass spectrometry, only the oxylipin 3-hydroxy 9:1 (a monounsaturated fatty acid containing a hydroxyl group on carbon 3) could be identified. Sequential digital imaging suggests that oxylipin-coated spindle-shaped ascospores are released from enclosed asci probably by protruding through an already disintegrating ascus wall.     

A new species ofLasiobolidium from Californian soil

Lasiobolidium gracile isolated from a soil sample collected from California, USA is described as a new species. This species is characterized by yellowish brown to reddish brown, nonostiolate ascomata with numerous, long straight appendages and a translucent peridium, subglobose to broadly clavate asci, hyaline to pale yellowish brown, ellipsoidal ascospores. It differs from the other species ofLasiobolidium in the straight and narrow appendages and the large ascospores. A key is presented separating the seven known species.     

MORPHOLOGY OF CHAETOMIUM ERRATICUM

Development of perithecia from single, uninucleate ascospores disclosed a homothallic condition for Chaetomium erraticum. This species was found to produce sessile ascogonial coil initials from uninucleate vegetative cells that become enveloped by hyphae formed at the base of the ascogonium. The ascogonium consists of several cells that are uninucleate or binucleate. A perithecium forms from numerous divisions and enlargement of the surrounding uninucleate cells. Differentiation of the perithecial cells results in the formation of a carbonaceous wall, perithecial hairs, and an ostiole lined with periphyses. A convex hymenial cluster of ascogenous cells forms in the lower half of the centrum from which typical croziers develop. Asci push up into the pseudoparenchyma cells of the centrum. The growth of the ascogenous system is in part responsible for increase in perithecial size. The breakdown of the pseudoparenchyma cells around the developing asci results in the formation of a central cavity in which ascospores are released when the asci deliquesce. No paraphyses are present. The type of development and features of the centrum of C. erraticum and other species of Chaetomium indicate a distinct Xylaria-type centrum.     

THE CENTRUM OF THE SOOTY MOLD ASCOMYCETE LIMACINULA SAMOENSIS

Centrum development in the sooty mold Ascomycete Limacinula samoensis von Hoehnel emend. Reynolds proceeds in an ascostroma which begins as a small cushion of somatic tissue and enlarges by multiplication of cells in an apical region and by cell enlargement. A two-layered ascocarp wall initially surrounds a pseudoparenchymatous core into which the bitunicate asci protrude. Interascal strands of pseudoparenchymatous tissue disintegrate at maturity of the ascocarp. An apical meristem eventually culminates activity with formation of a short ostiolate neck. Centrum development is homologous to the Dothidea type. The centrum development of other capnodiaceous fungi is reviewed.     

Bambusicolous fungi in Japan (3): a new combination, Kalmusia scabrispora

Leptosphaeria scabrispora collected from Phyllostachys bambusoides is reported from Japan. This species was described initially from China and has not been reported subsequently. Based on the morphological features of clypeate ascomata, long stipitate asci, and reddish-brown ascospores with median primary septum, it is transferred to the genus Kalmusia. The fungus produced a Leptodothiorella-like microconidial state in culture.