Helicogloea is an obscure genus of crusts in the rust-fungus subphylum Pucciniomycotina. Amongst the Helicogloea species, you might be most familiar with Helicogloea compressa, which is frequently found in its asexual form as light-colored pustules (sporodochia) on wood. The genus is otherwise composed primarily of rare and poorly studied species that produce thin crusts with a waxy to gelatinous consistency. Upon drying, many of these crusts become literally invisible, making study of fungarium material difficult. Microscopically, Helicogloea crusts are simple septate, without cystidia, have saccate (sac-like) probasidia, and produce very cool septate basidia with lateral sterigmata characteristic of Pucciniomycotina fungi. There are 25 species accepted in the genus Helicogloea. Species in the closely related genera Saccosoma (seven species) and Bourdotigloea (nine species) differ in having clamped hyphae or cystidia (Spirin et al. 2018).

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