Quercus garryana, Garry oak or Oregon white oak, is the dominant vegetation on the western edge of the Agate Desert, an alluvial fan capped with shallow clay loam over a cemented hardpan. The landform exhibits patterned ground with mounds and vernal pools. The oaks are associated with Ceanothus cuneatus and with native and exotic grasses. In preparation for a study of the biocomplexity of common mycorrhizal networks among oaks and grasses, we are examining the morphotypes of mycorrhizae on Quercus garryana. We sampled soil cores at distances half way to the canopy edge, at the canopy edge, and outside the canopy and have identified four morphotypes of ectomycorrhizae including extensive Cenococcum. Where Cenococcum dominates, few other morphotypes are found. In addition, endomycorrhizae with intraradical hyphae and vesicles also occur. Infection rates are 10-32% with lowest rates on roots under vernal pools and highest rates in areas of canopy overlap. Funded by NSF Grant DEB-9981337.

Key words: Cenococcum, endomycorrhizae, mycorrhizae, oaks, Quercus, vernal pools