Full name: Hebeloma fragrantissimum Velen. (1920)
Published: Ceske Houby: 395 (1919) ["1920"]
Taxonomic status: Heterotypic synonym of H. ischnostylum
Types: CZECH REPUBLIC: Hane, Kosirem west of Olomouc (approx. 49.5519°N, 17.03°E, alt. approx. 350 m a.s.l.) in willow thicket under Salix sp., Oct. 1919, Kaspar, det: J. Velenovsky (Lectotype. herbarium acc. no. PRC B157, HJB1000238). Lectotype designated by Beker et al., Hebeloma (Fr.) P. Kumm.: (2016) page 598 (MBT202532).

Original diagnosis: Magnitudine et habitu Hypholomati fasciculari simile, sed undique album. Pileo 1,5-3,5 cm diam., obtuse conico-campanulato, paulisper umbonato, subcarnoso, perfecte glabro, conspecte viscido, albo, aetate in squamulas parvas adpressas soluto, iam iuventute prorsus absque velo, margine involuto. Stipite longo, plerumque arcuato, 3-4 mm crasso, albo, glabro, basi saepe undulato-compresso et cavo, aetate citrine-inhalato (haud brunnescenti), apice granuloso. Lamellis confertis, latis, postice rotundato-liberis, ochraceis, acie albis et ciliatis. Sporis magnis, laete luteis, inaequalateraliter amygdaliformibus, 14-16 μm. Cystidiis numerosis, obtusis, fere capitato-cylindraceis. Odor dulcis (ut officina ad fabricationem alcoholi) penetrans. In caespitibus robustis (!) in fossis prope Košiře, Pragae, Kašpar legit, octobri 1919. Hebeloma sacchariolens probabiliter affine, sed autor scripsit: gregarium in nemoribus Saliceis et pileum centro ferrugineum eodem auctore habet.

English translation: In size and habit similar to Hypholoma fasciculare, but white in all parts. Pileus 1.5–3.5 cm diam. bluntly conico-campanulato, weakly umbonate, thin-fleshed, perfectly glabrous, distinctly viscid, white, when old breaking up in small, adpressed squamules, already when young absolutely without veil, with involute margin. Stipe long, frequently curved, 3–4 mm thick, white, glabrous, at base often undulating-compressed and hollow, with age turning lemon-yellow (not browning), with granulose apex. Lamellae crowded, broad, rounded-free, ochraceous, with white, ciliate edge. Spores large, pale yellow, unequally amygdaloid. 14–16 μm. Cystidia abundant, blunt, almost cylindrical-capitate. Odour sweet, penetrating (like in an alcohol factory). In robust (large) clusters (!) in a ditch near Košiře, Pragae, leg. Kašpar, oct. 1919. Probably close to Hebeloma sacchariolens, but, as the author writes: gregarious in Salix copse and with ferrugineous centre of pileus.

Commentary: The ‘original diagnosis’ above is the translation into Latin from the original Czech by Pilat, Opera Bot. Čechica 6: 136 (1948). Studies of the lectotype and the protologue show that this is a member of H. sect. Sacchariolentia. Being described with a white pileus, breaking up into small scales with age, and a 3–4 mm broad stipe, it agrees best with Hebeloma ischnostylum (Cooke) Sacc. and H. fusisporum Gröger & Zschiesch. Our morphological study reveals spores on average 11.0 × 5.9 µm, which is in disagreement with the protologue. Based on examination of other material of Velenovsky stored in this medium, we believe it is highly unlikely that the spores have shrunk. This spore size does fall within the range of H. ischnostylum, and we therefore conclude that this taxon is: = Hebeloma ischnostylum (Cooke) Sacc.