The Great Smoky Mountains National Park (GSMNP) has the largest tract of old growth forest with 40,000 hectares in the Tennessee-North Carolina region of eastern United States. The All Taxa Biodiversity Inventory (ATBI) program will attempt to complete a comprehensive inventory of all life forms in the park. This additional tree canopy study will include the first comprehensive sampling and inventory of the cryptogams (myxomycetes, macrofungi, mosses, liverworts, and lichens). A student research team spent six weeks during the summers of 2000 and 2001 collecting over 3,000 bark samples from over 200 trees representing 40 species. Using the double rope climbing technique, students scaled tree canopy heights up to 40 meters. A total of 2007 canopy samples from 141 trees yeilded 193 lichen taxa with 78 new records for the park. Lichens collected from non-canopy and ground habitats yeilded 56 new records The current GSMNP lichen accession list has 248 species which was increased by an additional 134 species from this field study. Noteworthy macrofungi included Lentaria byssidea, a small clavariod basidomycete on living black oak, and Marasmiellus opacus, a gilled basiodmycete on living red maple. Approximately 40 new records of Myxomycetes (plasmodial slime molds) were discoved in the park, including a new undescribed species of Diachea apparently restricted to the canopy of white oak and red cedar trees. Echinostelium elachiston is a new record from white ash and is only known from Kansas in the Untied States and the type locality in Greece. Comatricha penicillata is recorded for the first time outside of the type locality in Japan. The National Science Foundation, Division of Environmental Biology, Biotic Surveys and Inventories Program Award #0079058 and Discover Life in America Award #2001-26 funded this project.