Fungalpedia – Note 34 Heliogaster

Heliogaster Orihara & K. Iwase

Citation if using this entry: Fallahi et al. (2023) New genera in 2010-2011. Mycosphere (in prep)

Index Fungorum, Facesoffungi, MycoBank, GenBank, Fig 1.

The monotypic sequestrate genus Heliogaster was described in Boletaceae by Orihara et al. (2010). The genus accommodates a single species Heliogaster columellifer, formerly named Octaviania columellifera (Kobayasi 1937). It is usually found under Abies firma (Pinaceae) in Japan. Orihara et al. (2010) used morphological and nuclear large subunit (nLSU) and ITS sequence data to evaluate herbarium and fresh specimens of Octaviania columellifera and Octaviania asterosperma sensu lato (Japanese Octaviania asterosperma). They found these two species were identical in morphological and molecular characteristics and obviously diverse from the generally known Octaviania asterosperma. In the phylogenetic assay, they clustered in the same lineage with the boletoid mushroom-forming Xerocomus chrysenteron complex (Orihara et al. 2010). With this information, the new genus Heliogaster was proposed for Octaviania columellifera and the Japanese Octaviania asterosperma clade. It is characterized by sectioned to gasteroid basidiomata, and non-pulverulent gleba which is usually discolored when exposed to air. The columella is mostly present and relatively dendroid. Basidia are clavate to cylindro-clavate. Basidiospores are dextrinoid, conical to pyramidal, and relatively striate.

Fig 1Heliogaster columellifer (Redrawn from Orihara et al. (2010) (b, e), and Kobayasi (1937) (a, c, d, and f)). a Median section of fruiting body. b, c Section of Hymenium. d, e Mature basidiospore. f Section of peridium. Scale bars: a=2 cm; b, c, f=50 μm; d, e=10 μm.

The perisporium and ectosporium are present. There is no palisadoderm on the periodical surface that is found in every species of the Xerocomus chrysenteron complex (Orihara et al. 2010).

Type species: Heliogaster columellifer (Kobayasi) Orihara & K. Iwase


Kobayasi Y. 1937- Development and structure of a new species of Octaviania (Hymenogastraceae). Shokubutsugaku Zasshi 51, 291-299.

Orihara T, Sawada F, Ikeda S, Yamato M, Tanaka C, Shimomura N, Makoto H, Iwase, K. 2010-Taxonomic reconsideration of a sequestrate fungus, Octaviania columellifera, with the proposal of a new genus, Heliogaster, and its phylogenetic relationships in the Boletales. Mycologia 102, 108-121.

Entry by

Maryam Fallahi, Center of Excellence in Fungal Research, Mae Fah Luang University, Chiang Rai 57100, Thailand.

(Edited by Kevin D Hyde and Ruvishika S. Jayawardena)

Published online 23 May 2023