Suillus hypogaeus: First record of a truffle Suillus

ABSTRACT

Suillus (order Boletales) is a diverse genus of epigeous, mushroom-forming fungi native to temperate forests across the Northern Hemisphere; however, some species are also present in areas where Pinaceae has been introduced in the Southern Hemisphere. Unlike the closely related genus Rhizopogon, there are no described hypogeous, sequestrate species of Suillus. Here, we describe Suillus hypogaeus, the first known species of the genus with hypogeous, sequestrate sporocarps. Collections were made on Marys Peak in Benton County, Oregon, USA, at an elevation of 800 m in forests dominated by Pseudotsuga menziesii var. menziesii. The peridium is white, quickly staining pink to purple-reddish where bruised or cut. The gleba is pale yellow when young, becoming purple with maturity, and the basidiospores are obovoid, light yellow in KOH, and amyloid in Melzer’s reagent. Multilocus molecular phylogenetic analyses support the placement of S. hypogaeus among the Larix specialists in the spectabilis group of Suillus. Although Larix and Pseudotsuga are sister genera, Larix does not occur on Marys Peak or elsewhere in western Oregon. Suillus hypogaeus, therefore, represents both an independent origin of the hypogeous, sequestrate sporocarp within the Boletales and an independent host shift between Larix and Pseudotsuga within the genus Suillus.

KEYWORDS:

• Basidiomycota
• hypogeous fungi
• sequestrate fungi
• systematics
• 1 new taxon

ACKNOWLEDGMENTS

We thank the OSC herbarium and their staff for the loan of specimens. We would like to express our appreciation to the anonymous reviewers and executive editor Terry W. Henkel for suggestions that result in significant improvements in the manuscript.

DISCLOSURE STATEMENT

No potential conflict of interest was reported by the author(s).

SUPPLEMENTARY MATERIAL

Supplemental data for this article can be accessed online at https://doi.org/10.1080/00275514.2024.2361518

Additional information

Funding

This work was supported by funding from the Oregon Mycological Society, Sonoma County Mycological Society, North American Truffling Society, Puget Sound Mycological Society, and North American Mycological Association. C.G.P.P. thanks the Consejo Nacional de Ciencia y Tecnología (registro 262593, solicitud 438400) for supporting her education in the USA.