Three major hypotheses have been advanced for the adaptive nature of plant galls: nutrition, enemyavoidance, and microenvironment. Of these, the microenvironment hypothesis has been frequently invoked, but rarely tested directly. We tested this hypothesis in a population of Andricus quercuscalifornicus (Bassett) (Hymenoptera: Cynipidae) wasps inducing galls on Quercus lobata Née (Fagaceae) tree...

Mating patterns play a critical role in the maintenance of genetic variation. We analyzed the mating system in a recently fragmented population of the Andean oak (Quercus humboldtii) using four microsatellite loci. Five fragments in northeastern Colombia, South America, were selected consisting of 30.4 trees on average. We sampled about 30 seeds from three target trees in each fragment and geno...

Species in the present study were compared based on their morphology, growth characteristics in culture, and DNA sequences of the nuclear ribosomal RNA gene operon (including ITS1, ITS2, 5.8S nrDNA and the first 900 bp of the 28S nrDNA) for all species and partial actin and translation elongation factor 1-alpha gene sequences for Cladosporium species. New species of Mycosphaerella (Mycosphaerel...

Quercus affinis and Q. laurina are two closely related Mexican red oaks with partially overlapping distributions. Within the area of overlap, there are localities where morphological intergradation occurs. A previous hypothesis explained this pattern as a result of secondary contact between the two species, followed by hybridization and introgression. This possibility was analyzed here by exami...

Lithocarpus dahuoaiensis Ngoc & L. V. Dung, a new species from the Central highland of Vietnam, is described and illustrated. The new species is morphologically similar to Lithocarpus macphailii (M. R. Hend.) Barnett or Lithocarpus encleisocarpus (Korth.) A. Camus in having completely entire leaf margin, solitary cupule, long stalks of fruits, deeply cup-shaped or turbinate cupules, with a numb...

American chestnut (Castanea dentata [Marsh.] Borkh.) dominated the eastern forests of North America, serving as a keystone species both ecologically and economically until the introduction of the chestnut blight, Cryphonectria parasitica, functionally eradicated the species. Restoration efforts include genetic transformation utilizing genes such as oxalate oxidase to produce potentially blight-...

Oaks (Quercus, Fagaceae) are the dominant tree genus of North America in species number and biomass, and Mexico is a global center of oak diversity. Understanding the origins of oak diversity is key to understanding biodiversity of northern temperate forests. A phylogenetic study of biogeography, niche evolution and diversification patterns in Quercus was performed using 300 samples, 146 specie...

During surveys of Phytophthora diversity in natural and semi-natural Fagaceae forests in Austria, Italy and Portugal, four new cryptic species were isolated from rhizosphere soil samples. Multigene phylogeny based on nuclear ITS, ß-tubulin and HSP90 and mitochondrial cox1 and NADH1 gene sequences demonstrated that two species, P. tyrrhenica and P. vulcanica spp. nov., belong to phylogenetic Cla...

Universal primers for amplifying and sequencing a noncoding spacer between the atpB and rbcL genes of the chloroplast DNA were constructed from the published sequences of Marchantia (a liverwort), tobacco, and rice. Our results indicate an evolutionary trend of increasing spacer size from liverworts, through mosses, to vascular plants. This atpB-rbcL spacer is AT-rich, consistent with other chl...

Draft genomes for the fungi Ceratocystis fagacearum, C. harringtonii, Grosmannia penicillata, and Huntiella bhutanensis are presented. Ceratocystis fagacearum is a major causal agent of vascular wilt of oaks and other trees in the family Fagaceae. Ceratocystis harringtonii, previously known as C. populicola, causes disease in Populus species in the USA and Canada. Grosmannia penicillata is the ...