Bird's nest fungi, sphere throwers, & shotgun fungi
Bird's nest fungi.
Bird's nest fungi, sphere throwers, and shotgun fungi are all saprophytes, which grow on manure or decaying wood. Since these fungi live only on decaying plant matter, they do not harm living plants. In the garden, the tiny (under 1/4 inch tall) fungi are usually found on the surface of soil, which has been enriched with manure, sawdust, or wood chips. They can also be found on old boards used to edge garden beds and on wooden plant labels and stakes. The fungi are usually spread in manure, however, some species may occur as contaminants within seed mixes.
All of these fungi can forcibly eject their spores in hard egg-like structures called peridioles. These structures can be ejected one yard or more. The sticky spore cases adhere to plant foliage and other surfaces, including home siding and patio furniture.
These fungi are rarely noticed unless they are brought indoors on container-grown plants. The first sign is shiny black or dark brown objects resembling seeds or insects on the leaves. These are the egg-like structures that have been ejected by the fungi. If unsightly, they can be picked off the leaves. To help control these fungi, remove any fungal fruiting bodies from the surface of the soil. Repotting the plant in a potting medium that does not contain manure or wood should prevent the fungi from returning.
Peridioles of bird's nest fungi being ejected during a rainstorm.
Sphere throwers (Sphaerobolus spp.) grow on rotting wood in many of the same places as bird's nest fungi. The whitish or yellowish-pink immature fruiting bodies are round balls similar to immature bird's nest fungi. As the fruiting bodies mature, the outer layer of the ball peels back to form a cup with a single spherical peridiole inside. This cup is actually two cups, one inside the other, joined at the rim. Pressure builds up between the two cups, eventually causing the inner cup to explosively invert, or turn inside out. The force of the inversion launches the peridiole, which can travel more than five yards before sticking to any surface it impacts.
These ballistic fungi, each with its unique method of spore dispersal, can be a fascinating introduction to the world of fungi. A careful search of the damp corners of your garden in the fall will probably reveal numerous bird's nest fungi, sphere throwers, and shotgun fungi.
Alexopoulos, C.J. and C.W. Mims, Introductory Mycology, 3rd ed. John Wiley and Sons, New York, 1979.
Brodie, H.J., The Bird's Nest Fungi. University of Toronto Press, Toronto, 1975.
Brodie, H.J., Fungi--Delight of Curiosity. University of Toronto Press, Toronto, 1978. [Written in non-technical terms; an interesting introduction to many common fungi] Carolina Biological Supply Company sells cultures of Pilobolus and bird's nest fungi. 2700 York Road, Burlington, NC 27215 (919) 584-0381 or (800) 334-5551.
Chad Behrendt, Crystal Floyd