Leccinum engelianum

Klofac recognised this species while preparing a key to the European Boletales and named it in honour of Helmut Engel, whose earlier work had drawn attention to the material. The first specimen was gathered on 7 September 1979 beside a beech‑lined track south of Kassel (Hesse) and is preserved at the Munich herbarium. Although it was long treated as part of Leccinum atrostipitatum in a broad sense, Klofac demonstrated that a particular combination of field characters, microscopic features and simple chemical reactions justifies its recognition as a distinct species. He placed it in section Quercina on account of its reddish‑brown cap and its beech association. Key differences from both L. atrostipitatum and the superficially similar L. quercinum include its failure to bruise blue in standard tests, its flesh remaining free of blackening when cut, and the presence of fine blackish scales on the lower stipe.^[2]

The cap grows to about 5 cm in diameter, initially rounded then flattening out. Its surface is finely fibrous to velvety, with a bright reddish‑brown hue that often deepens at the margin. When bruised, the cap edge may slowly turn almost black, and slicing the flesh produces a brief wine‑red blush before it shifts to a grey‑violet tone. Beneath the cap are pale olive tubes up to 15 mm deep, narrowly attached to the stipe, with minute pores that develop brown‑black spotting as they age.^[2]

The stipe measures roughly 6 cm tall by 3.5 cm wide, narrowing towards a pointed base. The upper half is straw‑coloured with a faint network pattern, while the lower half bears fine dark scales or scabres. The white flesh is mild‑tasting with no distinctive odour and reddens where cut.^[2]

Microscopically, the mushroom yields a yellow‑brown spore print. Its spores are slender and fusiform, and the cap cuticle (pileipellis) comprises elongated cells bearing pigmented encrustations—traits that, along with the macroscopic characters, confirm its identity.^[2]