Armillaria mexicana, a newly described species from Mexico.

Armillaria mexicana (Agaricales, Physalacriaceae) is described as a new species based on morphology, DNA sequence data, and phylogenetic analyses. It clearly differs from previously reported Armillaria species in North, Central, and South America. It is characterized by the absence of fibulae in the basidioma, abundant cheilocystidia, and ellipsoidal, hyaline basidiospores that are apparently smooth under light microscope, but slightly to moderately rugulose under scanning electron microscope.

Insights into the phylogeny of Northern Hemisphere Armillaria: Neighbor-net and Bayesian analyses of translation elongation factor 1-α gene sequences.

Armillaria possesses several intriguing characteristics that have inspired wide interest in understanding phylogenetic relationships within and among species of this genus. Nuclear ribosomal DNA sequence-based analyses of Armillaria provide only limited information for phylogenetic studies among widely divergent taxa. More recent studies have shown that translation elongation factor 1-α (tef1) sequences are highly informative for phylogenetic analysis of Armillaria species within diverse global regions.

Rust disease of eucalypts, caused by Puccinia psidii, did not originate via host jump from guava in Brazil.

The rust fungus, Puccinia psidii, is a devastating pathogen of introduced eucalypts (Eucalyptus spp.) in Brazil where it was first observed in 1912. This pathogen is hypothesized to be endemic to South and Central America and to have first infected eucalypts via a host jump from native guava (Psidium guajava).

Morphological and molecular methods to identify butternut (Juglans cinerea) and butternut hybrids: relevance to butternut conservation.

Butternut (Juglans cinerea L.) is a native, cold-tolerant, hard-mast species formerly valued for its nuts and wood, which is now endangered. The most immediate threat to butternut restoration is the spread of butternut canker disease, caused by the exotic fungus Sirococcus clavigignenti-juglandacearum Nair, Kostichka & Kuntz.