Ross W. Davidson

Wood-Staining Fungi Associated with Bark Beetles in Engelmann Spruce in Colorado

Four species of the Ophiostomataceae have been found associated with Dendroctonus engelmanni Hopkins in bark of dying Picea engelmannii Parry in Colorado. Leptographium engelmannii, the perfect sta...

Two American Hardwood Species of Endoconidiophora Described as New

A fungus recorded as Endoconidiophora coerulescens Munch was found by Davidson (2) and Verrall (6) to be one of the most important fungi causing stain of hardwood logs and lumber in the South. During the earlier study (2) it was not observed on pine logs or lumber even where both pine and hardwood logs were handled by the same mill. Verrall (6) isolated it twice from pine wood but found it prevalent and important only on hardwoods. In Europe Munch (5) illustrated E. coerulescens on pine wood, and Lagerberg, Lundberg, and Melin (3) isolated it only from stained spruce and pine. A further reason for differentiating the pineand spruce-inhabiting E. coerulescens of Europe from the fungus found on American hardwoods by Verrall and the author is the fact that the latter does not produce the amylacetate odor, which is characteristic of E. coerulescens Munch (3). Cultures of the European fungus were obtained from the Centraalbureau Voor Schimmelcultures and compared with isolates of the American fungus. These comparisons show that although the two are quite similar morphologically there are several consistent and significant differences. Therefore, the hardwood lumber fungus is described here as a new species. The second species described in this paper produces a bananaoil odor but differs morphologically from E. coerulescens and other described species. It was isolated from chestnut oak bark.

Two Common Lumber-Staining Fungi in the Western United States

Two species of the Ophiostomataceae group of wood-staining fungi are reported on sapwood of coniferous lumber in the western United States. A species very similar to Endoconidiophora coerulescens b...

The Fungus Causing Pecky Cypress

In a preliminary report on the cause of pecky decay of bald cypress, Taxodium distichum (L.) Rich. (5), it was stated that basidiocarps of a Stereum had been collected from this host and that cultures derived from spores of this Stereum were similar to cultures isolated from typical pecky decay. In the present paper this Stereum is described as a new species and compared with the better known S. sulcatum Burt, which it closely resembles. Several specimens of the cypress Stereum have been collected in the past by pathologists interested in cypress decay. Von Schrenk obtained a specimen, apparently from a cypress log, in Louisiana in March 1898. This is the specimen reported from Louisiana by Burt (2) as S. sulcatum. Long collected specimens of the same species on a cypress log in Texas in May 1918. Neither Long (16) nor von Schrenk (29) indicated that this Stereum might be connected with pecky cypress. One other specimen was collected by A. S. Rhoads near Gainesville, Florida, in December 1943. These three basidiocarp specimens and the one recently collected in Mississippi (5) suggest that the fungus is widespread on cypress in the South. Collections made since this study was started indicate that the species is common in mature cypress stands. The Stereum on cypress is especially interesting because its basidiocarps resemble those of S. sulcatum; however, on more careful examination, differences are apparent. Cultures of the two are quite distinct; those of S. sulcatum obtained from hosts such as Engelmann spruce, Picea engelmannii Parry, and hemlock, Tsuga canadensis (L.) Carr., show no resemblance to cultures of the species on cypress. These differences are detailed in the following descriptions.

The Life Histories of Botryosphaeria Melanops and Massaria Platani

Among the specimens sent into the Washington laboratory of the Division of Forest Pathology for identification, there are occasional fungi of more than ordinary interest, either because of their scarcity or because, in the course of the work incidental to their identification, some new information is secured regarding them. These criteria apply to specimens of the two fungi with which this paper is concerned.

Fungi causing decay in wooden boats.

In a survey of decay in boats (5), started in 1941, an attempt was made to isolate and identify the fungus involved in each case investigated. Decay fungi were obtained from about one-third of the samples from which isolations were attempted. In many instances the fungus was inactive in the selected wood sample or molds had invaded the decayed wood so completely that the fungus causing the damage could not be isolated. In some samples the fungus obtained may not have been the cause of the principal damage but in general those fungi recovered most frequently are believed to be among the more important species causing decay. Certain fungi, such as Poria incrassata (Berk. & Curt.) Burt, which die rather quickly on drying (10), probably were involved in some cases of extensive damage although they were not identified during this limited survey. A more exhaustive study would result in obtaining additional species.

Species of Sclerotinia from Grand Mesa National Forest, Colorado

This paper consists of some of the results of a collecting trip made by the senior author to the Grand Mesa National Forest, Colorado, during the period of June 12 to July 20, 1930. Al? though the fungi here discussed represent only a small percentage of the total number of collections, it seems that the species of Sclerotinia were sufficient in number and interest to justify a separate account. The Grand Mesa National Forest is on the western slope of the Continental Divide in the west-central part of Colorado, and Grand Mesa Mountain, where most of the species of Sclerotinia were obtained, has sufricient moisture from melting snow and summer rains to make possible a rich fungus flora. Most of the fungi were found near the top of the mountain, at an elevation of about 10,000 feet; Sclerotinia gregaria, however, occurred approximately 2,000 feet lower, several miles down the mountain from Mesa Lakes.

Notes on Tropical Rusts with Descriptions of Two New Species

By checking these specimens with the numbers and dates given in Arthurs paper, it was found that many were duplicates of those already studied. In most instances all data except num? bers and date of collection were missing. S. F. Blake identified many of the hosts and others were determined from the rust present. The interesting rust on Senecio sp. was found by S. F. Blake while examining some specimens of plants from Venezuela. Specimens of the two new species have been sent to Dr. Arthur and he also believes them to be undescribed.

Some New Species of Ascomycetes on Coniferous Hosts

The fungi here described include one pyrenomycete and four discomycetes collected on conifers in various localities of the United States. Specimens cited are deposited in the Mycological Collections of the Bureau of Plant Industry; type material of the Cenangium has also been sent to the herbaria of the New York Botanical Garden and the University of Michigan and to the Farlow Herbarium of Harvard University.

A new species of Dothiora on Aspen and Willow.

Ascocarps innate-erumpent, depressed-pulvinate, circular or irregular in outline, densely gregarious, smooth, black; locules single or occasionally several, thick lenticular, astomous (FIG. 1, A, B); asci polysporous (24 or more spores), cylindric-clavate, short stipitate, 90-115 X 12-15 u, aparaphysate; spores when mature muriform with 3 transverse septa and frequently 1 or rarely 2 longitudinal septa in the upper cells, clavate, constricted in the middle, upper half broader, hyaline, 15-18 X 5-6 x. Conidia in culture hyaline, 1-celled, 8-15 X 4-6 e in size, borne on the mycelium as in Dematium; pycnidia in culture on sterilized willow twigs resemble those of the genus Dothichiza Lib., producing hyaline, 1-celled spores, 6-10 X 3-5 /u in size.