Systematic study of truffles in the genus Ruhlandiella, with the description of two new species from Patagonia

ABSTRACT

Ruhlandiella is a genus of exothecial, ectomycorrhizal fungi in the order Pezizales. Ascomata of exothecial fungi typically lack a peridium and are covered with a hymenial layer instead. Ruhlandiella species have nonoperculate asci and highly ornamented ascospores. The genus was first described by Hennings in 1903 to include the single species, R. berolinensis. Since then, mycologists have uncovered Ruhlandiella species in many locations around the globe, including Australia, Spain, Italy, and the USA. Currently, there are four recognized species: R. berolinensis, R. peregrina, R. reticulata, and R. truncata. All were found near Eucalyptus or Melaleuca trees of Australasian origin. Recently, we discovered two new species of Ruhlandiella in Nothofagaceae forests in South America. They regularly form mitotic spore mats directly on soil in the forests of Patagonia. Here, we formally describe these new species and construct the phylogeny of Ruhlandiella and related genera using a multilocus phylogenetic analysis. We also revise the taxonomy of Ruhlandiella and provide an identification key to accepted species of Ruhlandiella.

KEYWORDS:

• Exothecium
• hypogeous fungi
• Nothofagaceae forests
• Pezizaceae
• Pezizales
• Sphaerosoma
• Muciturbo
• 3 new taxa

ACKNOWLEDGMENTS

We wish to thank the Administración de Parques Nacionales of Argentina for kindly authorizing our collecting expeditions in Parque Nacional Nahuel Huapi and Parque Nacional Lanín under Projecto 2016/720 (to E. Nouhra), the Chilean Corporacion Nacional Forestal (Gerencia de Areas Silvestres Protegidas) for providing permission to collect fungi in Puyehue National Park and the Magallanes Forest Reserve under permit No. 014/2014 (to M.E.S.), and the curators from the herbaria of CUP, FH, UC, OSC, K, and S and Mr. Ángel Suárez for generously sending fungal specimens. We thank Dr. Camille Truong for contributing a specimen of Ruhlandiella patagonica.

Additional information

Funding

This work was supported by the US National Science Foundation grant DEB 1354802 (to M.E.S.), a Fellowship from Harvard University, and the UF Institute of Food and Agricultural Sciences IFAS (to M.E.S.). The David Rockefeller Center for Latin American Studies at Harvard University also supported this work with funding to D. H. Pfister for collecting expeditions in Patagonia. The Royal Thai Government provided funding for graduate study to N.K.