CRYPTOCOLAX—A NEW GENUS OF FUNGI (ASPERGILLACEAE) FROM THE EOCENE OF OREGON

Abstract

THE CLARNO FORMATION of Eocene age in northcentral Oregon contains a varied assortment of fossil plant remains. These include leaves (Chaney, 1948) and structurally preserved ferns (Arnold, 1952); fruits and seeds (Scott, 1954), and wood (Scott and Barghoorn, 1955). The fruits and seeds, from an outcrop in Wheeler County near the type locality of the formation, are accompanied by logs and numerous pieces of silicified wood. The fruit and seed assemblage is unusual among American early Tertiary floras in showing a marked relationship to the London Clay flora from the Eocene of England (Reid and Chandler, 1933). In order to evaluate the significance of this relationship on a broader basis than that furnished by the fruits alone, an investigation of the fossil woods from the Clarno formation has been undertaken by the writer. Preliminary examination of the fossil woods has revealed that over 25 distinct entities are represented. Although most of the woods are well preserved, there is ample evidence of the ubiquitous presence of fungi in the form of hyphae penetrating the tracheary elements. The fungal remains thus far found in the woods from the Clarno formation consist chiefly of vegetative hyphae. However, several specimens of the wood of one species belonging to the Fagaceae (Castanop,sis?) contain a fungus whose septate hyphae bear both asexual spores and non-ostiolate sexual reproductive structures. These cleistothecia contain numerous ascospores. Another wood specimen representing a species of the Magnoliaceae (Magnolia?) also has similar cleistothecia within its vessels. The fungi, Ascomycetes assignable to the family Aspergillaceae (Eurotiaceae) , are unusual in that their sexual stages are preserved and in that their cleistothecia are borne in the lumina of the vessels. Although exceptions are known among modern forms, the ascocarps of most Ascomycetes are borne superficially rather than within the substrate. The recent discovery by Tyler and Barghoorn (1954) of fungal remains, together with algae, in Precambrian chert from Canada establishes for the fungi a fossil record as long as that of any other group of plants. Fossil fungi have been reported from a wide range of geologic horizons and in association with diverse plant groups (Seward, 1898; Pia, 1927). Most of the occurrences are