Taphrina populina

A species restricted to the leaves of Populus, also known as Taphrina aurea, on which it produces small blisters that, upon maturity, become covered with a powdery, bright yellow layer, this colour being due to the numerous oily droplets inside the asci.

Asci cylindrical, with a rounded apex and tapered base, 65 to 90 µm long, 18 to 22 µm wide, containing numerous refractive golden-yellow oil droplets inside, apparently 8-spored, although these ascospores typically multiply by budding within the ascus, leaving the entire interior packed with spherical secondary spores known as blastospores.

Free mature ascospores not observed; according to literature, subglobose to ellipsoidal, smooth, hyaline, 4 to 6 µm long and 3 to 4 µm wide.