Larry F. Grand

A beaded endotrophic mycorrhiza of Northern and Southern Red Oak.

An endotrophic mycorrhiza was found during a study of the morphological forms of ectotrophic mycorrhizae of northern red oak (Quercus rubra L.) and southern red oak (Q. falcata Michx.). The endotrophic type was frequently found on short roots of 7 northern red oaks and 4 southern red oaks from each of 3 locations in the Mountain, Piedmont, and Sand Hills regions of North Carolina. The mycorrhizae are beadlike (FIG. 1), with 1-9 beads in succession, dull white, and range from 2 to 8 mm in length and 0.4 to 0.8 mm in diam. Root hairs were not observed. Occasionally branched forms were found and in all instances, the branches were also beaded. To avoid mistaking roots for those of surrounding plants, all root samples were carefully traced back to the tree in question. Microscopically the type is a typical vesicular-arbuscular endotrophic mycorrhiza with intracellular hyphae (FIG. 2), well developed arbuscular haustoria (FIG. 3), and intracellular vesicles (FIG. 4). There was no evidence of a fungal mantle or Hartig net. Attempts to grow the fungal symbiont in pure culture failed. This endotrophic mycorrhiza is similar to those formed by species of Endogone (Gerdemann, personal communication). Most mycorrhizae formed by species of Quercus are ectotrophic (Trappe, 1962); however, Henry (1933), reported an ectendotrophic mycorrhiza on Q. rubra. To find an endotrophic mycorrhiza commonly occurring on red oak is unusual and to my knowledge, the form described has not been previously reported. Descriptions of beaded endotrophic mycorrhizae have been reported on roots of Acer platanoides L. (Henry, 1933), A. rubrum L. (McDougall, 1914; Henry, 1934; Vozzo and Hacskaylo, 1964), A. saccharum Marsh. (Kessler, 1966), Amelanchier canadensis (L.) Medic. (Henry, 1934), Cornus florida L. (Henry, 1933), Ilex opaca Ait. (Vozzo and Hacskaylo, 1964), Liquidambar styraciflua L. (Vozzo and Hacskaylo, 1964; Filer and Toole, 1966), and Nyssa sylvatica Marsh.; Populus alba L.; Prunus serotina Ehrh.; and Sorbus americana Marsh. (Henry, 1934). The beaded endotrophic mycorrhiza described in this report is simi408

Cercospora Caricis from Cyperus Esculentus (Yellow Nutsedge): Morphology and Cercosporin Production

involved in disease development. The fungus infected plants in the greenhouse and is considered to be a pathogen of yellow nutsedge (Blaney and Van Dyke, unpubl.). Cercospora caricis Oud. is the only Cercospora species previously reported from yellow nutsedge (Boewe, 1964). The objectives of this study were to compare the North Carolina isolates of the fungus with C. caricis collections and to determine if cercosporin was produced in culture. Leaves of yellow nutsedge with dark brown lesions were collected in 1986 from Johnston and Wake Counties in North Carolina. The length and diameter of 100 conidia, conidiophores, and stromata of the fungus from a minimum of 4 different leaves per location were measured, and measurements of structures produced in the field were recorded separately from those produced in moist chambers.

Phylogenetic and phenotypic characterization of Fomes fasciatus and Fomes fomentarius in the United States

The wood-decay fungi Fomes fasciatus and F. fomentarius share many morphological characters that historically have made species delimitation challenging. We examined morphological, molecular and physiological characters of basidiomata and pure cultures of F. fasciatus and F. fomentarius sampled from multiple plant hosts and geographic regions in the United States to determine whether they support separation of the two species. We find that mean basidiospore size is significantly larger in F. fomentarius and represents the most informative morphological character for delineating the species. Basidiomata and pore-surface shape provided additional resolution of the species, but these characters often overlap and are more variable than basidiospore size. Phylogenetic analyses of ITS and RPB2 sequences suggest that F. fasciatus and F. fomentarius represent distinct evolutionary lineages. The two species share less than 88% maximum identity for the ITS region. Limited intraspecific sequence variation at each locus also was observed. In vitro experiments of hyphal-growth response to a wide range of temperatures support differences in physiology between the two species.

A NEW SPECIES OF BOLETUS, SECTION LURIDI, FROM NORTH CAROLINA'

SUMMARY Boletus piedmontensis, a new species, is described from North Carolina. Distinguishing characteristics are the pinkish buff to olive buff pileus, discolorous tubes, distinctive caulocystidia which are arranged in dense reddish clusters resembling reticulations, and pronounced amyloid bodies within the hyphae of the cuticular and subcuticular layers of the pileus. During the summer of 1969 several collections were made of a species of Boletus in section Luridi in the Piedmont region of North Carolina. Attempts to identify this species in published works failed. Initially the species was tentatively identified as Boletus satanus Lenz var. americanus Coker & Beers (1943); however, attempts to locate specimens of this species in the University of North Carolina at Chapel Hill herbarium were unsuccessful. It is assumed that the collections by Coker are lost or misplaced. The species described here differs from the description of B. satanus var. americanius in the reticulately arranged pruina on the upper portion of the stipe, bluing of the pores, bulbous to subbulbous stipe and lack of bitter-acid taste. The purpose of this paper is to put on record an undescribed species of Boletus from North Carolina as a part of the continuing study of the

A new species of Pythium producing multiple oospores isolated from bentgrass in North Carolina.

Pythium plurisporium sp. nov. was isolated from diseased roots and crowns of bentgrass (Agrostis palustris) from two golf courses in North Carolina. The species is distinguished from other Pythium spp., except P. multisporum, in the production of multiple oospores (1-6 per oogonium) and by the occurrence of some oogonia (ca 20%) with a distinctive pedicel with two to four swollen elements originating at vary? ing distances below the oogonia. The development of two or three oogonia from the same branch of the oogonial hypha was infrequently observed (ca 2%).

A previously unrecognized southern species of Boletus.

Species concepts currently accepted by investigators in the Boletaceae vary from exceedingly broad to very concise and restricted. In the Boletus edulis group for instance, we find in Singers (1967) classification that B. edulis is maintained as a collective species even to the inclusion of B. separans Peck. At the same time Singer maintains Xerocomus coniferarum Singer as a species distinct from X. subtomentosus on very slight differences, they are keyed out on the fleeting color change caused by ammonia vapors on X. spadiceus. We find no logical explanation for this dual type of species concept in a single group such as the boletes. In contrast, Smith and Thiers (1970) have found that in this family there is a consistent level at which species can be readily recognized, and that such concepts do much to clarify the phytogeography of the group as well as associations with specific forest trees. The purpose of this article is to place on record a species hitherto unrecognized because of having been included in a broad concept of B. separans by Coker and Beers (1943). The species described in the following account is amply distinct from B. separans (Pecks type) in that the caulocystidia acquire a bluegreen color of the wall in KOH, and in that the cells of the pileus

Occurrence of Boletus Piedmontensis in North Carolina and Georgia

Dr. J. W. Gerdemann, University of Illinois, generously supplied the Illinois isolate for our experiments. The Bend isolate was collected and maintained in pot culture by Mr. Iwan Ho of the Pacific Northwest Forest and Range Experiment Station, Forestry Sciences Laboratory, Corvallis, Oregon. Statistical analyses were not performed because the results reported in this paper are self evident, i.e., either germination occurred or it did not.