Genea, Genabeaand Gilkeyagen. nov.: ascomata and ectomycorrhiza formation in a Quercuswoodland

Geneaand Genabeaare considered ectomycorrhizal (EM) symbionts of higher plants, but because of their hypogeous habit, dark coloration and the small size of their ascomata, relatively little is known about these genera. Ascomata of six morphological species of Geneaand one of Genabeawere frequently collected at a single site in xeric Quercuswoodlands of California’s Sierra Nevada foothills. While most collections were easily referred to known species, those putatively identified as Genea harknessiiand Genea arenariawere problematic. Genea harknessiicollections appeared relatively homogenous based on morphology, but significant ITS variation revealed by rDNA sequencing suggested cryptic species diversity. Specimens of G. arenariaapproximated the brief, original species description except for abundant clumps of septate setae formed at the apex of peridial warts. To verify the identity of this species we reexamined the holotype and analyzed morphology and ITS sequences of G. arenariaascomata from a wide geographic range. To authenticate the EM status of Geneaand Genabeawith Quercuswe collected healthy EM of Quercus douglasiiand Quercus wislizeniiand compared their ITS sequences to those from ascomata. We detected nine distinct ITS types of Geneaand Genabeaon roots. Two new species described here as Genea bihymeniatasp. nov. and Genea cazaresiisp. nov., were discovered during study of herbarium specimens. A phylogenetic analysis of 28 s rDNA from Geneaand Genabeaindicated three distinct lineages: Genea, Genabeaand a third represented by Genea intermedia. For the latter we propose Gilkeya gen. nov.to accommodate the single known species, Gilkeya compacta comb. nov.A dichotomous key to all known Genea, Genabeaand Gilkeyaspp. from western North America is presented.