Pilobolus crystallinus

The most reliable way to recognize Pilobolus crystallinus is by its behavior as much as its shape: a slender, translucent stalk no more than 2 to 4 centimeters tall, topped by a small, dark sporangium that sits ready to be launched. The fungus typically develops beneath the surface of its substrate at first, since sensitivity to oxygen inhibits sideways growth of the hyphae until conditions are right.

Development follows six distinct stages, as described by McVickar and later refined by Ootaki and colleagues. The sporangiophore first elongates at its tip without rotating, then forms a sporangium at the apex. Growth then pauses briefly before a subsporangial vesicle swells beneath the sporangium. As the spores mature, the hypha just below this vesicle keeps elongating, building pressure until the vesicle finally bursts and hurls the sporangium into the air.

Examined under scanning and transmission electron microscopy, the surface of the sporangium shows a fine texture of crystals in two distinct sizes. The larger crystals enclose spines with a central pore, a structural detail linked to how the spore case grips and adheres to whatever surface it strikes after launch.

Observation records for Pilobolus crystallinus are recorded across every month of the year, with counts rising through spring and peaking sharply in September, when observations reach roughly 291, well above the 64 recorded in January. Elevated numbers also appear from July through October, suggesting the fungus is most frequently noticed in late summer and early autumn.

These figures come from GBIF occurrence records, which reflect presence observations only, not abundance, population size, or the species' full native range. A peak in reported sightings during a given season indicates when people are more likely to have recorded the fungus, not necessarily when it is most abundant or active.

Given its dependence on fresh animal dung as a growth substrate, its recorded presence likely tracks conditions favorable for fruiting on that material, though the distribution data alone does not specify particular habitats or regions.

1. Pilobolus crystallinus adheres its spore-laden sporangium to blades of grass or other vegetation so that grazing animals will eat it along with their forage.
2. The spores survive passage through an animal's digestive system entirely intact, germinating only after they emerge in fresh dung.
3. The dance company Pilobolus, founded at Dartmouth College in New Hampshire around 1971, took its name from this genus of fungus and went on to become a well-known American cultural institution built around athletic, collaborative movement.
4. Despite standing only 2 to 4 centimeters tall, this fungus can fire its sporangium up to 2 meters, a distance many times its own height.