Paraglomus majewskii sp. nov. (Glomeromycota) is described and illustrated. It forms single spores, which are hyaline through their life cycle, globose to subglobose, (35-)63(-78) μm diam, sometimes egg-shaped, 50-70 × 65-90 μm, and have an unusually narrow, (3.2-)4.6(-5.9) μm, cylindrical to slightly flared subtending hypha. The spore wall of P. majewskii consists of an evanescent, short-lived outermost layer, a laminate middle layer, and a flexible innermost layer, which adheres tightly to the middle layer. None of the spore wall layers stain in Melzer's reagent. In single-species cultures with Plantago lanceolata as the host plant P. majewskii formed arbuscular mycorrhizae staining violet in trypan blue. P. majewskii has been isolated from several, distant geographic regions and from different habitats. In phylogenetic analyses of partial nrDNA SSU and LSU sequences the fungus formed mono-phyletic group with Paraglomus species; however it represents a well separated distinct lineage. Its nrDNA sequences are highly similar to in planta arbuscular mycorrhizal fungal sequences from different habitats in Spain and Ecuador.

Desert truffles belonging to Terfezia are well known mycorrhizal members of the mycota of the Mediterranean region and the Middle East. We aimed to test (i) whether the morphological criteria of Terfezia species regularly collected in Spain enable their separation and (ii) whether the previously hypothesized edaphic/biotic specificity of one group could be confirmed by study of a larger number of specimens. The species T. arenaria and T. claveryi can be identified unambiguously by morphological characters. We consider T. leptoderma as a distinct species while several lineages of similar spiny spored Terfezia truffles with cellular peridium were detected that have no obvious anatomical differences. Several species treated generally as synonyms of T. olbiensis have been described in this group, and because they cannot be unambiguously assigned to separate lineages we propose to consider the group as the T. olbiensis species complex. A high level of intrasporocarpic variation of the nrDNA ITS was detected in the T. olbiensis species complex, especially in one of its lineages. We detected no exclusive specificity to either plant associates or soil, except in T. leptoderma, which was associated with Quercus spp. and cistaceous plants on acidic soils. Nevertheless the clades showed a tendency either to associate with Quercus/Helianthemum/Cistus or Pinus hosts. Specimens having distinct anatomical features, reticulate spores and cellular peridium formed a separate group in the molecular phylogenetic analyses of nrDNA ITS and LSU regions; for these specimens we propose a new species, Terfezia alsheikhii sp. nov.

The arbuscular mycorrhizal (AM) fungi colonizing the sporophytes of the eusporangiate rattlesnake fern (Botrychium virginianum, Ophioglossaceae) in its Hungarian population were investigated in the present study. Different regions of the nrRNA gene complex were analyzed using two different primer sets. These produced similar results for the detected AM fungi phylotypes. Several AM fungal lineages were associated with sporophytes of B. virginianum. Phylogenetic analyses of different partial small subunit datasets grouped one lineage into the Gigasporaceae, showing similarities with Scutellospora sequences. In addition to unidentified Scutellospora phylotypes, it is possible that S. gregaria also colonized the fern. Several AM fungal phylotypes colonizing the sporophytes grouped into Glomus group A. They did not form distinct clades but grouped with sequences of AM fungi with different geographic and host origins. One main lineage clustered into the widespread G. fasciculatum/G. intraradices group and one into the subgroup GlGrAc, while others had no affinity to the subgroups of Glomus group A. As AM fungal phylotypes associated with B. virginianum seem to belong to widespread AM fungal taxa and show no specificity to this fern, we suppose that the previously described special anatomy of AM of B. virginianum is determined by the plant.

A new arbuscular mycorrhizal fungal species of genus Glomus, G. perpusillum (Glomeromycota), forming small, hyaline spores is described and illustrated. Spores of G. perpusillum were formed in hypogeous aggregates and occasionally inside roots. They are globose to subglobose, (10-)24(-30) microm diam, rarely egg-shaped, oblong to irregular, 18-25 x 25-63 microm. The single spore wall of G. perpusillum consists of two permanent layers: a finely laminate, semiflexible to rigid outer layer and a flexible to semiflexible inner layer. The inner layer becomes plastic and frequently contracts in spores crushed in PVLG-based mountants and stains reddish white to grayish red in Melzer's reagent. Glomus perpusillum was associated with roots of Ammophila arenaria colonizing sand dunes of the Mediterranean Sea adjacent to Calambrone, Italy, and this is the only site of its occurrence known to date. In single-species cultures with Plantago lanceolata as host plant, G. perpusillum formed vesicular-arbuscular mycorrhiza. Phylogenetic analyses of partial SSU sequences of nrDNA placed the species in Glomus group A with no affinity to its subgroups. The sequences of G. perpusillum unambiguously separated from the sequences of described Glomus species and formed a distinct clade together with in planta arbuscular mycorrhizal fungal sequences found in alpine plants.