Puccinia coronata

On living leaves of Rhamnus frangula, causing yellowish to reddish necrotic spots on the upper surface corresponding to spermogonia; on the underside of the leaf, aecia develop clustered in circles, producing aeciospores (aecial or primary stage of the species).

Aecia cup-shaped, 0.5 to 0.7 mm in diameter, with a raised, lacerate, whitish margin and yellowish to orange interior, arranged in circles or elongated clusters of 15 to 100 or more specimens, reaching a cluster length of up to several cm.

Aecial wall hyphae polygonal to hexagonal, 26 to 35 µm long, 19 to 24 µm wide, with thick walls up to 5 µm.

Aeciospores globose to slightly angular, 20 to 25 µm long, 15 to 22 µm wide, with a broad hyaline wall and dense orange-yellow granular cytoplasm in the center.