Summary:
Features include 1) a spherical to somewhat spherical, flat or depressed fruitbody that is white with red tones but becomes brown to yellow-brown, 2) a spore mass that is pale brown to yellow brown with maze-like cavities generally radiating away from the small stem, 3) a branching columella, 4) underground growth associated with conifer roots, and 5) microscopic characters including spores 13-18 x 7-10 microns with about 9-12 ridges and 4-spored basidia with short sterigmata. Trappe(13) mentions a var. odora nom. prov. States and Fogel.

Chemical Reactions:
KOH immediately a faint dark red-orange on peridium; FeSO4 pale green on peridium; Melzer''s reagent, quickly red-brown on peridium, soon fading, (Castellano)

Interior:
pale brown to yellow brown; locules up to 0.05-0.2cm, labyrinthiform, generally radiating away from the stem, empty, (Castellano), "cinnamon" to "Sayal brown"; cavities labyrinthiform, empty, minute, (Dodge)

Odor:
weak, unpleasant, (Dodge)

Microscopic:
spores "13-18 x 7-10 microns including sterigmal appendage and epispore, 13-18 x 5-7 microns excluding epispore", elliptic, "often somewhat flattened at the apex", ornamentation of 9-12, sometimes forking, longitudinal ridges, 0.5-1.5(2) microns tall, 2-3 microns broad, "ridge margins humped to cleft, grooves between ridges smooth to finely crenulate", in Melzer''s reagent spores "red-orange singly, dark red-orange in mass", in KOH "pale green-yellow singly, yellow in mass", slowly cyanophilic, wall +/-1 microns thick, "sterigmal appendage truncate, prominent, 1-2 microns wide"; basidia 4-spored, (12)18-30(45) x 6-9 microns, clavate, thin-walled; subhymenium "of subpolygonal cells 10-30 x 5-13 microns, progressively smaller as the subhymenium merges into the linear hyphae composing the trama"; trama narrow, of hyphae 3-5 microns wide, colorless, thin-walled, gelatinizing when old, oleiferous hyphae present; columella of hyphae 1-5 microns wide, colorless, inflated to 18 microns wide adjacent to septa, inflated areas filled with granules and spines +/-1 micron long, "projecting from the inner wall surface toward the interior"; peridium 65-150 microns thick, "of thick-walled, napiform cells" 17-40 microns in diameter, (Castellano), spores 12-16 x 6-8 microns, apex rounded, with about 10 smooth striations, "ochraceous-tawny", short pedicellate; basidia 4-spored, 10-14 x 6-8 microns, clavate, sterigmata short; septa 90-180 microns thick, "composed of slender highly gelified hyphae"; peridium not seen, (Dodge)

Notes:
Gautieria otthii is found at least in OR, CA, and Switzerland, (Castellano). The var. odora nom. prov. States and Fogel is said to be infrequent from BC to ID and northern CA (Trappe).

Synonyms and Alternate Names:
Antrodia malicola (Berk. & M.A. Curtis) Donk Persoonia
Trametes malicola Berk & M.A. Curtis