Mushrooms use convectively created airflows to disperse their spores

Significance Mushroom spore dispersal is usually described as a two-phase process: active ejection of spores clear of the gill surface by surface tension catapults, followed by a passive phase in which the spores are carried by whatever winds are present beneath the mushroom cap. Here, we show that control extends into the second phase of dispersal: water vapor loss creates slow airflows that carry spores out from under the mushroom cap and potentially tens of centimeters into the air. In addition to clarifying why mushrooms have such high water needs, and providing a mechanism by which spore dispersal can occur even in a low-wind environment, our work shows that the physics of apparently passive dispersal may be under organismal control.