Remarks. The genus Gerronema was created by Singer (1951) to accommodate three omphalinoid-clitocyboid species from South America, where he later transferred some species traditionally placed in Omphalina (Singer 1964) as well as all taxa of this genus recognized in Bigelow’s 1970 monograph (Singer 1986). Singer differentiated them by the presence of intraparietal pigments or incrusting pigments in Omphalina and intracellular pigments in Gerronema. On the other hand Clemençon (1982) validated the genus Chrysomphalina, created by Hass (1962), to accommodate two omphalinoid species C. chrysophylla (Fr.) Clemençon (≡ Gerronema chrysophylla [Fr.] Singer) and C. strombodes (Berk. & Mont.) Clemençon (≡ G. strombodes [Berk. & Mont.] Singer) characterized by 2–8 cm wide, gray, brown-gray to brown-yellow pileus, yellow lamellae, hymenophoral trama ‘‘pachypodial’’, the presence of intracellular pigments, a yellowish spore powder and the presence/absence of clamp connections.
Gerronema ss. Singer (Singer 1961, 1964, 1975,1986) has been considered heterogeneous by many authors and further Redhead (1986) restricted Gerronema to species having sarcodimitic tissues, including the Singer’s type G. melanomphax Singer. Later Norvel et al (1994) recognized three Chrysomphalina species, the type C. chrysophylla, C. aurantiaca (Peck) Redhead and C. grossula (Pers.) Norvell et al, characterized by lignicolous, clampless, carotenoid forming, omphalinoid taxa with inamyloid thin walled spores, pachypodial subhimenia and monomitic tissues, retaining the clamped C. strombodes in Gerronema by its sarcodimitic tissues. In addition these authors found differences between the American collections of this taxon (the original C. strombodes, described from Ohio) and the European collections, which he named G. xanthophyllum (Bres.) Norv (= Omphalia hypoxantha Bres.) by a pileus with appressed squamules composed of fascicles of clavate to clavate-pedicellate pileocystidia with brown intracellular pigments in the former and a fibrillose pileus without pileocystidia in the later.
Bañares, Ángel, Esperanza Beltrán & Marcel Bon. Gerronema wildpretii sp. nov. (Agaricales, Basidiomycetes) a New Species from the Canary Islands. Mycologia 98.3 (2006): 455-459. http://www.jstor.org/stable/20444722