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The distribution and seasonal patterns of arbuscular mycorrhizal fungi activity were studied in an inland boreal salt pan site in north-central Manitoba. Semipermanent study regions were set up in each of five vegetation zones along a continuous salinity gradient. Roots of Hordeum jubatum, Distichlis stricta, Agropyron trachycaulum, Sonchus arvensis, Spartina gracilis, and other species were collected from the study regions over six time periods: April, June, July, August, and October of 1991, and May of 1992. These roots were used to quantify mycorrhizal colonization, as well as arbuscule and vesicle formation. Arbuscular mycorrhizal fungi were prevalent in the three vegetation zones with lowest soil salinity, with > 40% of the observed root pieces colonized. Colonization was

Six halophytic plants including Atriplex patula, Glaux maritima, Hordeum jubatum, Puccinellia nuttalliana, Salicornia rubra, and Suaeda depressa were collected at various growth stages throughout the growing season of the summers 1982 and 1983 from an inland salt marsh at Delta, Man. Washed root and shoot pieces of each plant species were plated on culture medium, incubated, and surveyed for cauloplane and rhizoplane fungi. A total of 31 taxa were isolated including 3 asco-mycetes, 2 coelomycetes, 1 zygomycete, and 25 hyphomycetes. Morphological features, plant type, cultures, and taxonomic deposition are presented for each fungal taxon.

Wood and soil samples from Churchill and Great Whale (Hudson Bay) were surveyed or baited for recovery of marine fungi. A total of 14 ascomycetes, 7 fungi imperfecti, and 13 zoosporic fungi are reported. Amylocarpus encephaloides, Cephalosporium sp., Corollospora comata, Dictysporium pelagicum, Haligena amicta, Haligena elaterophora, Halosphaeria maritima, H. mediosetigera, H. quadriremis, H. stellata, Herpotrichiella ciliomaris, Nais inornata, Papulospora halima, Phialophora sp., Phoma sp., Schizochytrium aggregatum, Thraustochytrium aggregatum, T. multirudimentale, T. pachydermum, T. roseum, Trichocladium achrasporum, and Zalerion varium are recorded for the first time from arctic marine sites. Each species is discussed in terms of morphological features, taxonomic deposition, and ecological considerations.

Lignicolous substrates, i.e., wood and leaves, were collected from 10 São Paulo State locations and 2 Pernambuco State sites. These were subsequently surveyed and incubated and (or) washed, macerated, and plated on culture media. Six types of wood and mangrove leaves were placed in exposed and buried digestors, recovered, surveyed, incubated, and resurveyed for marine fungi. Of a total of 69 isolated taxa, 32 species, including 24 ascomycetes, seven fungi imperfecti, and one basidiomycete, are discussed. Included are Ceriosporopsis cambrensis; C. halima; Corollospora lacera; C. maritima; C. pulchella; C. trifurcata; Crinigera maritima; Didymosphaeria enalia; Haligena viscidula; Halosarpheia fibrosa; Halosphaeria appendiculuta; H. cucullata; H. galerita; H. hamata; H. maritima; H. mediosetigea; H. quadricornuta; H. salina; Leptosphaeria cfr. marina, Leptosphaeria sp.; Lignincola laevis; Lulworthia medusa (f. grandispora); Mycosphaerella sp.; Torpedospora radiata; Ceriosporopsis halima anamorphic form; Cirrenalia tropicalis; Clavariopsis bulbosa; Periconia prolifica; Scolecobasidium? arenarium; Septoria sp.; Trichocladium achrasporum; and Nia vibrissa. Morphological features, collection sites, substrates, slides, cultures, taxonomic deposition, and ecological considerations are presented for each species. A possible Scolecobasidium–Septoria–Mycosphaerella anamorphic–teleomorphic association is suggested.

Various dung substrates including that of arctic fox, arctic hare, arctic wolf, lemming, musk-ox, polar bear, rock ptarmigan, and snow goose were collected from the Churchill region, Resolute Bay region, Scogan Lowland, Sverdrup Lowland, Truelove Lowland, and Truelove Valley. These collections were incubated and surveyed for coprophilous fungi. Of 20 taxa recorded Ascobolus stictoideus, Cheilymenia coprinaria, Coprobia granulata, Lilliputia rufula, Sporormiella bipartis, Sporormiella dubia, Sporormiella minima, Sporormiella septenaria, and a Zopfiella sp. are first reports for Arctic sites. Taxonomic problems are discussed in some detail for Sporormiella intermedia and Thelebolus polysporous.

Phylctochytrium arcticum Barr and Rhizophlyctis harderi Uebelmesser are reported as additional taxa in soils of Truelove Lowland (Devon Island, N.W.T.) and Nowakowskiella spp., Olpidium pendulum Zopf, Pythium irregularae Buisman. Pythium spp., Phlyctochytrium arcticum, and Rhizophydium sphaerotheca Zopf are readily detectable as active organisms in Lowland microhabitats. Species diversity is greatest in mesic and warm soils and species composition of water-logged soils is different than dry soils. Soil acidity effects on distribution are discussed and autecological considerations of Nowakowskiella elegans and R. sphaerotheca with respect to pH, percentage N, C, and P, milliequivalents Ca2+ and Mg2+, moisture, and temperature are presented.

Morphological development of an isolate of Schizochytrium aggregatum Goldstein and Belsky is presented. This isolate differs in several respects from those originally described. Monads, diads, and tetrads are smaller. Rhizoids may originate from monads as well as diads and tetrads. Variously shaped swellings along the course of the rhizoids and interconnection of one rhizoidal system with another can occur. Monads sometimes function as sporangia.The genus is emended to include the variation of this isolate.

Zoosporic fungi, mainly Chytridiales, are recorded from 61 sites in 10 different Base Camp Lowland habitats. Of the eight genera and 19 species recovered Catenophlyctis (Phlyctorhiza) variabilis, Hyphochytrium catenoides, Nowakowskiella elegans, Olpidium pendulum, Rhizophydium pollinis-pini, R. sphaerotheca, Rhizophydium sp. (utricularae?), and Pythium irregularae have been reported from the Arctic before. Chytriomyces annulatus, C. poculatus, Nowakowskiella macrospora, N. ramosa, Rhizidium verrucosum, Rhizophydium angulosum, R. coronum, R. eleyensis, R. karlingii, Rhizophydium sp. (nodulosum?), and Rhizophydium sp. (patellarium?) are reported for the first time from the Arctic.

The criteria generally used in distinguishing taxa among the Chytridiales are size and structure of the zoospores, sporangium wall ornamentations, discharge papillae and tubes, presence or absence and structure of apophyses, nature and structure of rhizoids and number and position of rhizoidal axes, thallus development and relation to the substratum, monocentricity or polycentricity, and operculation. A review of the literature, however, reveals that these criteria are not sharply defined but highly variable and unstable for purposes of exact identification. This variability has become evident from a study of 10 single spore isolates of an Entophlyctis species collected in western Canada and the U.S.A. and grown on pollen grains and a synthetic medium. A comparison of the variations common to all isolates relates this species to several different established species of the genus which grade into one another and result in only three valid taxa, E. apiculata, E. crenata, and E. reticulospora. Also, the variations of the isolates relate this Entophlyctis sp. to different genera, subfamilies, families, and series, and make various current taxonomic dispositions and concepts of little value.

Zoosporic fungi are reported for the first time from soils of the Queen Charlotte Islands. Seventy-two species in 21 genera from 128 sites are included in this report. Developmental details and taxonomic problems are discussed for selected species.

Fifty-four species of chytrids, chytridiaceous fungi, and Actinomycetales in 18 genera are reported in 140 collections from 32 coastal and interior locations. Morphological details are presented for some species.

Temperature and salinity responses of 57 isolates of various taxa of the Chytridiales and Blastocladiales were determined after maintenance of isolates under controlled conditions for a minimum period of 6 months. Differences and similarities among isolates generally seem constant in time and over several isolates of the same species from the same collection. Since these differences and similarities within a species tend to correlate with habitat types, they possibly represent ecotypes.