Christopher Walker

Names and epithets in the Glomales and Endogonales

In a recent paper, Almeida (1989) wrote about the names and epithets used in the Endogonales sensu lato , commenting on their derivations, and providing a list of names he considered should be used in preference. Almost all of these changes were erroneous, and, with four exceptions, the original names should be retained. Two new corrections of orthographic errors are made.

Species of Gigaspora (Endogonaceae) with roughened outer walls

Examination of soil samples from sand dunes of the eastern seaboard of the U.S.A. revealed three previously undescribed species of Gigaspora producing spores with roughened outer walls. Spores of G...

GIGASPORA ERYTHROPA, A NEW SPECIES FORMING ARBUSCULAR MYCORRHIZAE

Gigaspora erythropa, a newly described species, occurs commonly in sand dunes of the Atlantic coast of the United States and the Bahamas and also in a silt-loam apple orchard in New York. The species is characterized by its dark orange- to red-brown, smooth-walled spores which possess a brittle outer wall group consisting of a thick, colored exterior wall and 1 or 2 thin, hyaline walls, and a flexible inner wall group composed of a thick, pale yellow laminated wall and a thin membranous innermost wall. Gigaspora erythropa formed mycorrhizae with arbuscules but not with vesicles in pot cultures with apple, onion, sorghum, and ryegrass. The species was also associated, but not proven mycorrhizal, with Ammophila breviligulata, Solidago sempervirens, and Lathyrus japonicus var. glaber. Examination of soil samples from around the root zones of beachgrass {Am? mophila breviligulata Fern.), beachpea {Lathyrus japonicus Willd. var. glaber (Ser.) Fern., and seaside goldenrod {Solidago sempervirens L.) growing in the barrier sand dunes of the south coast of Rhode Island revealed a previously undescribed species of the arbuscular-mycorrhizal genus Gigaspora. The species was later found in an apple orchard {Pyrus malus L.) and was pot-cultured by D. Miller (Horticulture Department, Iowa State University). Spores were recovered from sand dune samples by a modification of the wet-sieving technique. Approximately 40 g of sand was placed in a 1500 ml beaker to which was added about 600 ml water. The sand/water mixture was shaken vigorously for ca. 30 sec, the sand allowed to settle, and the water solution quickly decanted into a Buchner funnel holding a #4 Whatman filter paper 9 cm in diam. Suction was applied, the paper removed, and spores were located on the filter paper with a dissecting microscope. This method is very suitable for beach and dune sands, but is not effective for more complex soils with clays or much organic matter. Extraction of spores from the apple orchard soil was by a centrifugation/sugarflotation technique (11). Collections are deposited in the herbarium at Oregon State University (OSC), the Farlow Herbarium (F), and at Kew (K). Wall description terminology and standardized lettering are those suggested by Walker (10).

Some endogonaceous mycorrhizal fungi of the Santa Catalina Mountains in Arizona

natural life cycle of Entomophthora egressa. Expl. Mycol. 1: 259-265. Vandenberg, J. D., and R. S. Soper. 1975. Isolation and identification of Entomophthora spp. Fres. (Phycomycetes: Entomophthorales) from spruce budworm Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae). J. N. Y. Entomol. Soc. 83: 254-255. Weber, H. 1979. Ultrastructural evidence for viruses in Ascomycetes and Basidiomycetes. Pp. 364-404. In: Viruses and plasmids in fungi. Ed., P. Lemke. Marcel Dekker, New York.

Acaulospora nicolsonii, a new endogonaceous species from Great Britain

A new species of endogonaceous fungus, Acaulospora nicolsonii , is described from Great Britain. Attempts to obtain the species in pure pot culture have failed, though it sporulated in a pot containing Zea mays and mycorrhizal Glomus species. Wound healing of the type previously thought to be confined to Gigaspora spp. was noted on a hypha attached to a sporiferous saccule of A. nicolsonii .

A new fungal species forming arbuscular mycorrhizas: Glomus viscosum

A species of Glomus forming arbuscular mycorrhizas was established in pot culture with several plants. The fungus forms abundant hyaline to white spores in loose clusters. In addition to the normal spore wall which is continuous with the wall of the subtending hypha, the spores of this species produce an apparently mucilaginous outer coating, resulting in the adherence of minute soil particles which were shown to be composed of soil particles by EDAX analysis. The fungus is named Glomus viscosum in reference to the sticky outer coating. The spores, germination characteristics, and mycorrhizas are described and illustrated, and the symbiotic behaviour is discussed.

Differences in mycorrhizal status among clones of Sitka spruce

Abstract Cuttings of Sitka spruce clones with the same maternal parentage were rooted under mist and examined after they had been grown for a year in a forest nursery. All short roots were found to be mycorrhizal, but one clone differed from the others in the proportion of the roots colonized by different mycorrhizal fungi. Substantial clonal differences in root morphology were partially explained by these mycorrhizal differences. The significance of the host-fungus genotype interaction is discussed.

Endogone lactiflua forming ectomycorrhizas with Pinus contorta

A mycorrhizal association between Pinus contorta (lodgepole pine) and Endogone lactiflua is described.

Sitka spruce mycorrhizas

Relatively little research has been done on mycorrhizas of Sitka spruce, although greenhouse studies have confirmed that its growth can be improved by the introduction of mycorrhizal fungi. Work in nurseries is difficult under British conditions and it probably will be necessary to disinfest soil in seedbeds before mycorrhizal treatment can be applied. Results from forest trials show that inoculation with selected mycorrhizal fungi can give significant early growth effects, though how long these will persist is unknown. In such work, careful attention must be given to selection of controls. Features covered in this review include a discussion of fungi mycorrhizal with Sitka spruce, identification of mycorrhizas, nutrient uptake, and growth enhancement of seedlings and transplants.

Lectotypification of Scutellospora auriglobosa (Glomales)

The type material of Scutellospora auriglobosa Hall has been found to contain more than one species of Scutellospora . A lectotype is selected and the fungus re-described.