Sori in inflorescences that are usually ±completely destroyed and transformed into blackish brown granular-powdery spore masses; sometimes only single flowers are attacked and, rarely, the panicle rachis and leaves are infected. Sori initially covered by a white to light brown peridium of fungal origin which ruptures irregularly and flakes away to expose the mass of spore balls mixed with groups of sterile cells and numerous columellae (remnants of vascular bundles and fungal elements). Columellae long, sinuous or stout, thread-like.
Spore balls 60–100 µm long, composed of numerous loosely connected spores.
Spores globose, subglobose to ovoid or slightly irregular, 10.5–14.5 × 10–13 µm, light olivaceous brown, densely and minutely echinulate.
Sterile cells in irregular persistent groups, rounded on the free surface, flattened on the contact surfaces, 8–16 µm long, hyaline to yellow-tinted, smooth, with a few oil droplets in each cell.
Spore germination resulting in 4-celled basidia on which lateral and terminal basidiospores are produced.
