Pilobolus crystallinus, commonly known as the "dung cannon" or "hat thrower", is a species of fungus belonging to the Mucorales order.

The injury was caused by the projection of the sporangia which covered the flowers and leaves of the roses as if profusely dusted with black pepper.

[1]This fungus normally grows beneath the surface – a sensitivity to oxygen inhibits radial growth at the hyphae.

This is followed by stage V, where the spore matures, and the region of hypha directly below the subsporangial vesicle continues elongating.

[4] Scanning and transmission electron microscopy has shown that the surface of the sporangium is covered with crystals of two distinct sizes.