Full name: Hebeloma magnimamma (Fr.) P. Karst. (1879)
Published: Bidrag Kännedom Finlands Natur Folk 32: 477 (1879)
Taxonomic status: This is a Hebeloma but we have not been able to unambiguously determine the species.
Basionym: Agaricus magnimamma Fr. (1863)

Types: (Holotype. herbarium acc. no. S 50509b, HJB1000213).

The holotype is a collection described from Sweden, near Reymeyra in Ostrogotia. Plate of von Post and Fries, mentioned in the protologue.

Homotypic synonyms: Hebelomatis magnimamma (Fr.) Locq. (1979) [“1977”]

Original diagnosis: Ad terram ad Reymyra Ostrogothiae von Post. A. petiginoso remotius affinis, at pluribus gravioribus notis distinctus. Stipes obsolete fistulosus, fibrosus, uncialis, raro ultra, lin. crassus, aequalis, sed passim flexuosus, glaber, nudus, absque velo manifesto, gilvo-pallescens. Pileus disco pro ratione admodum carnosus, hinc in umbonem mammiformem insigniter extuberans, absque indusio floccoso-sericeo A. petiginosi, ½ vix umquam 1 unc. !atus, umbone excepto e convexo planus, primo testaceus, in ambitu laevis, demum expallens, lutescens, non vero hygrophanus. Caro alba, marginem versus tenuis. Lamellae obtuse adnatae, subsinuatae, confertae, lin. latae, e pallido demum ferrugineae. A. petiginosus, magnimamma et odini statura minuta Naucoriarum reliquis recedunt, sed stipes fibrosus ad Hebelomata ducit.

English translation: Terrestrial near Reymeyra in Ostrogotia collected by von Post. Remotely elated to A. petiginosus, differing in several important characters. Stipe finally hollow, fibrous, 2.5 cm long, rarely more, 2.5 mm thick, equal, but sometimes flexuous, glabrous, smooth, without distinct veil, dull yellow, pallescent. Pileus relatively fleshy at centre, provided with a remarkable mammiform umbo, without the floccose-sericeus veil of A. petiginosus. 1.3 hardly up to 2.5 cm broad, plano-convex except for the umbo, brick at first, entirely smooth, then pallescent, becoming yellowish, not distinctly hygrophanous. Context white, thin towards margin (of pileus). Lamellae bluntly adnate, subsinuate, crowded, 2.5 mm broad, pale then rusty brown. A. petiginosus, A. magnimamma and A. odini have the stature of a small Naucoria, but are distant because of the fibrous stipe which is more like Hebeloma.

Commentary: Given the small stature and the lack of a veil, this species is almost certainly from Hebeloma sect. Denudata and likely to be either Hebeloma luteicystidiatum or H. pusillum. However, without more information we cannot, unambiguously, interpret this taxon.

Full name: Agaricus magnimamma Fr. (1863)
Published: Monographia Hymenomycetum Sueciae Vol 2 2: 299 (1863)
Taxonomic status: This is a Hebeloma but we have not been able to unambiguously determine the species.
Is basionym of: Hebeloma magnimamma (Fr.) P. Karst. (1879); Hebelomatis magnimamma (Fr.) Locq. (1979) [“1977”]

Types: (Holotype. herbarium acc. no. S 50509b, HJB1000213).

The holotype is an icon of a collection described from Sweden, near Reymeyra in Ostrogotia. Plate of von Post and Fries, mentioned in the protologue.

Commentary: See Hebeloma magnimamma (Fr.) P. Karst.

Full name: Hebelomatis magnimamma (Fr.) Locq. (1979) [“1977”]
Published: Flore Mycologique Vol III - Text. Cortinariales A: 146 (1979) ["1977"]
Taxonomic status: This is a Hebeloma but we have not been able to unambiguously determine the species.
Notes: Nom. inval. (Art. 45.1 - Melbourne).

Basionym: Agaricus magnimamma Fr. (1863)

Types: (Holotype. herbarium acc. no. S 50509b, HJB1000213).

The holotype is an icon of a collection described from Sweden, near Reymeyra in Ostrogotia. Plate of von Post and Fries, mentioned in the protologue.

Homotypic synonym of: Hebeloma magnimamma (Fr.) P. Karst. (1879)

Commentary: See Hebeloma magnimamma (Fr.) P. Karst.