STUDIES ON WESTERN AMERICAN PEZIZALES - COLLECTING AND DESCRIBING ASCOMATA - MACROSCOPIC FEATURES

Collecting practices and suggestions for describing the macroscopic ch aracters of Pezizalean ascomata are presented. They are based on studi es of the Pezizales from the conterminous United States west of the Gr eat Plains. New terms (athecium, exothecium, ptychothecium, pulverothe cium, stereothecium) for several types of ascomata in the Pezizales ar e introduced. Athecia are undifferentiated clusters of asci and paraph yses on a weft of hyphae. In an exothecium, the exterior of the ascoma is covered by the hymenium; in a ptychothecium a distinct, typically convoluted, hymenium is partly to entirely enclosed; in a pulverotheci um the asci develop within an initially hollow enclosed region and dis integrate at maturity, leaving a powdery spore mass; in a stereotheciu m the asci are clustered or scattered in a solid or slightly chambered /veined gleba completely enclosed by a peridium.