Fungi of a Long Island oak–birch forest. III. Distribution and survival of ascospores in the A horizon

Abstract

A 1-year survey of soil ascomycetes in the A horizon of an oak–birch forest was conducted using the selective Warcup steaming technique. Fourteen species, including two sclerotial anamorphs, belonging to seven genera were isolated. Their propagules were rare and did not exceed an average of 300 per gram of dry soil, except in the fall when numbers increased fivefold. Only Coniochaeta nepalica and an unidentified Eupenicillium species were isolated at every sampling period. Survival of ascospores of C. nepalica and the coprophilous fungus Sordaria fimicola introduced into the A horizon was tested. Both the indigenous and foreign ascospores showed no loss of viability during 210 days of incubation in soil, but approximately 15% of the Sordaria spores were ruptured as soil particles shifted during freeze–thaw cycles. The latter had no measurable effect on the much smaller ascospores of Coniochaeta.