Interactions between host tree species and ectomycorrhizal fungi are important in structuring ectomycorrhizal communities, but there are only a few studies on host influence of congeneric trees. We investigated ectomycorrhizal community assemblages on roots of deciduous Quercus crassifolia and evergreen Quercus laurina in a tropical montane cloud forest, one of the most endangered tropical forest ecosystems. Ectomycorrhizal fungi were identified by sequencing internal transcribed spacer and partial 28S rRNA gene. We sampled 80 soil cores and documented high ectomycorrhizal diversity with a total of 154 taxa. Canonical correspondence analysis indicated that oak host was significant in explaining some of the variation in ectomycorrhizal communities, despite the fact that the two Quercus species belong to the same red oak lineage (section Lobatae). A Tuber species, found in 23% of the soil cores, was the most frequent taxon. Similar to oak-dominated ectomycorrhizal communities in temperate forests, Thelephoraceae, Russulaceae and Sebacinales were diverse and dominant.

The ecological importance of ectomycorrhizal (EM) fungi in tropical ecosystems is increasingly recognized, but few studies have used molecular methods to examine EM fungal communities in tropical forests. The diversity and composition of the EM community on Quercus crassifolia in a tropical montane cloud forest in southern Mexico were characterized using DNA sequencing of single root tips. Individual root tips commonly harbored multiple fungal species that resulted in mixed polymerase chain reaction (PCR) products. By cloning and performing gel extractions on mixed PCR samples, we identified two or more EM fungi on 26% of the root tips. When non-EM fungi were considered, this figure increased to 31% of root tips. A total of 44 EM taxa and nine non-EM taxa were detected on roots from 21 soil cores (104 root tips). Taxa in the families Russulaceae, Cortinariaceae, Inocybaceae, and Thelephoraceae were frequent. This is the first study to characterize the belowground EM community in a tropical montane cloud forest.

Tropical rain forests have a high richness of plant species. However, the richness of insect species associated with the forest canopy is still poorly known. Estimates of arthropod fauna have followed several approaches from surveys on a single or few trees (Erwin 1988,1990) to regional sampling of specific insect guilds such as gall-inducing insects (Fernandes & Price 1988, Lara & Fernandes 1996, Price et al. 1998).

Lobelia alanae sp. nov. from Puebla and Veracruz, Mexico, is described from four known populations in tropical deciduous forests from 153 to 700 m elevation. This new species is compared to the closely related Lobelia porphyrea, a species known only from the type collection in the state of Hidalgo. Lobelia alanae can be separated from L. porphyrea by its height, hypanthium, calyx lobes and fruit. Based on the strongly reticulate-foveolate seed coats, L. alanae is hypothesized to be a new member of section Lobelia, previously comprising 22 species nearly endemic to the eastern U.S.

This is an open access article under the terms of the Creat ive Commo ns Attri bution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.