Two new species of Sistotrema s.l. (Cantharellales) from Japan with descriptions of their ectomycorrhizae.

We describe two new species of resupinate Sistotrema sensu lato (Cantharellales) collected in Japan: S. flavorhizomorphae and S. chloroporum. Both species have urniform basidia with more than four sterigmata and monomitic hyphal system, oil-rich hyphae in subiculum, which is typical for this genus. Sistotrema chloroporum is characterized by poroid hymenophore partly yellowish-green, basidia 4-6-spored, medium-sized basidiospores (4.5-6.5 × 3.5-6 µm), and broadleaf forest habitat. Sistotrema flavorhizomorphae is characterized by hydnoid-irpicoid hymenophore, bright yellowish rhizomorphs, basidia 6-8-spored, small basidiospores (3-3.5 × 2.5-3 µm), and pine forest habitat. Phylogenetic trees inferred from the fungal nrDNA ITS and LSU and the rpb2 sequences supported that both species were distinct and grouped with other ectomycorrhizal Sistotrema and Hydnum species, but their generic boundary was unclear. Mycorrhizae underneath basidiomes of both species were identified and described via molecular techniques. Mycorrhizae of S. chloroporum have similar characteristics to those of other Sistotrema s.l. and Hydnum species, i.e., S. confluens and H. repandum, whereas S. flavorhizomorphae has a distinct morpho-anatomy, for example, a distinct pseudoparenchymatous mantle. Comprehensive characterizations of basidiomes and mycorrhizae improve the taxonomic analysis of mycorrhizal species of Sistotrema s.l.

In-vitro symbiotic germination of seeds of five mycoheterotrophic Gastrodia orchids with Mycena and Marasmiaceae fungi.

We performed in-vitro germination tests on seeds from five Gastrodia orchids (G. confusa, G. elata var. elata, G. elata var. pallens, G. nipponica, and G. pubilabiata) using one Marasmiaceae and two Mycena isolates. Mycena sp. 1 promoted germination of all five Gastrodia orchids, with root and/or tuber formation observed in G. confusa, G. nipponica, and G. pubilabiata. No additional growth was observed in the other two orchids. Mycena sp. 2 induced G. confusa, G. elata var. elata, and G. nipponica germination, whereas Marasmiaceae sp. 1 induced G. nipponica and G. pubilabiata germination. Phylogenetic analyses indicated that the two Mycena isolates represent distinct lineages within the Mycenaceae. Mycena sp. 1 and Marasmiaceae sp. 1 are closely related to Mycena abramsii and Marasmiellus rhizomorphogenus, respectively. Our results imply that Mycena and marasmioid fungi play important roles in early development in Gastrodia species, and that Mycena fungi in particular may be common mycobionts of Gastrodia species. Root and/or tuber development was observed with four plant-fungus combinations, implying that these associations persist throughout the life cycle, whereas G. elata var. elata may require different associates over time. Our findings will contribute to elucidating the mycorrhizal associations of mycoheterotrophic orchids throughout their life cycle.

Description of a new species of Gerhardtia (Lyophyllaceae, Agaricales) from Japan based on morphological and molecular phylogenetic analyses and live culture characteristics.

We describe a new species of Gerhardtia from Japan based on basidiomata morphology, live culture characteristics, and molecular phylogenetic analyses. Gerhardtia venosolamellata is found on broad-leaf litter, and is characterized by tricholomatoid to marasmioid basidiomata, an off-white to pale salmon-pink pileus surface with faint marginal striae, subdistant lamellae with lateral veins, a tomentose to strigose stipe base with hyphal strands generating arthroconidia measuring 4-7 × 2-3 µm, cyanophilic, elongate-ellipsoid to cylindrical, slightly verrucose or undulate basidiospores measuring 4.5-6 × 2.5-3 µm, and cyanophilic basidia measuring 25-35 × 5-6 µm and containing siderophilous granules. Phylogenetic analyses based on the internal transcribed spacer and large subunit regions of the fungal nrDNA indicates that G. venosolamellata is related to G. sinensis and G. highlandensis, but differs from the former with respect to basidiomata color, basidiospore shape, and habitat. An isotype specimen of G. highlandensis exhibited relatively close lamellae without veins, and slightly larger basidiospores (4.5-6.5 × 2.5-3 µm). Cultured mycelia of G. venosolamellata produced arthroconidia measuring 4.5-8.5 × 2.5-3 µm with both schizolytic and rhexolytic secession on MA and PDA media, and chlamydospores occasionally covered with crystals on MA and MYG media.