Full name: Agaricus longicaudus β. albus Schulzer [as "A. (Hebeloma) longicaudus β. albus"] (1870)
Published: Verhandlungen der Kaiserlich-Königlichen Zoologisch-Botanischen Gesellschaft in Wien 20: 193 (1870)
Taxonomic status: We have not been able to unambiguously determine the current genus of this name.
Types: Not designated. Described from Northern Hungary.

Original diagnosis: Halbgesellig in Rw und Fw, Hut bald flach ausgebreitet, kreisrund, fleischig, die glatte Haut bei feuchtem Wetter klebrig, weiss, im Centrum kaum wahrnehmbar gelbbraunlich, 1-1½ unc. breit. Lamellen dicht, anfangs etwas entrandet mit einer Spitze angeheftet, bald aber frei und abgerundet, bei 2 unc. breit, erst trüb-rosenfarbig, dann blass zimmetbraun. Strunk verbogen, namentlich am Fusse seitlich gekrümmt, fast überall gleich dick, erst voll, dann hohl, 2-3 unc. dick, 1¾-3 unc. lang, Weiss, glänzend, mit feinen lockern weissen Flöckchen bedeckt. Fleisch Weiss. Sporen oval, beinahe verkehrt-eiförmig, 0,01 mm lang, dunkel purpur-rostbraun. Geruch nach Moder, unangenehm; Geschmack süsslich, nicht schlecht.

English translation: In small groups, pileus quickly expanding, circular, fleshy, the glabrous pileus is viscid in moist weather, white, with a faint yellow-brown tinge at centre, 2.5–4 cm wide. Lamellae crowded, at first emarginate with tooth, but soon rounded-free, about 5 mm broad, sordid pink at first then pale cinnamon. Stipe flexuous, curved towards base, almost entirely equal, solid then hollow, 5–7 cm thick, 3–7 cm long, white, shiny, covered with fine, loose flocks. Context white. Spore ovate, almost obovoid, 10 μm long, dark purple-rusty brown. Odour like mud, unpleasant. Taste sweetish, not unpleasant.

Commentary: It is not possible from the protologue to say what species this is, but being described with dull pink coloured lamellae, a stipe covered with loose white focks, purple rusty brown spores and a foetid odour, this is most likely not a Hebeloma.

Full name: Agaricus longicaudus Pers. (1801): Fr. (1821)
Published: Synopsis Methodica Fungorum (Gottingen): 332 (1801)
Taxonomic status: This is a Hebeloma but we have not been able to unambiguously determine the species.
Is basionym of: Hebeloma longicaudum (Pers.) P. Kumm. (1871); Hebeloma crustuliniforme var. longicaudum (Pers.) Quadr. (1985) ["1984"]; Derminus longicaudus (Pers.) Henn. (1898); Hebelomatis longicaudum (Pers.) Locq. (1979) [“1977”]; Hylophila crustuliniformis var. longicauda (Pers.) Quél. (1886); Hylophila longicauda (Pers.) Quél. (1888)

Types: Not designated. There is no original or authentic material in Persoon's herbarium at L.

Commentary: See Hebeloma longicaudum (Pers.) P. Kumm.

Full name: Agaricus longicaudus var. radicatus Cooke (1886)
Published: Handbook of British Fungi Edn. 2: 164 (1886)
Taxonomic status: Heterotypic synonym of H. birrus
Is basionym of: Hebeloma longicaudum var. radicatum (Cooke) Sacc. (1887); Hebeloma radicatum (Cooke) Maire (1908); Hebelomatis radicatum (Cooke) Locq. (1979) ["1977"]

Types: Cooke, Illustr. Br. Fungi: 164 (1884) t. 416, lectotype (icon) designated by Beker et al., Hebeloma (Fr.) P. Kumm.: (2016) page 609 (MBT203034)

This collection was mentioned within the protologue, so was clearly part of the original material.

Commentary: See Hebeloma radicatum (Cooke) Maire.

Full name: Derminus longicaudus (Pers.) Henn. (1898)
Published: Hymenomycetineae: 243 (1898)
Taxonomic status: This is a Hebeloma but we have not been able to unambiguously determine the species.
Basionym: Agaricus longicaudus Pers. (1801): Fr. (1821)

Types: Not designated. There is no original or authentic material in Persoon's herbarium at L.

Homotypic synonym of: Hebeloma longicaudum (Pers.) P. Kumm. (1871)

Commentary: See Hebeloma longicaudum (Pers.) P. Kumm.