Sphaerobolus | |
---|---|
Sphaerobolus stellatus | |
Scientific classification | |
Kingdom: | Fungi |
Phylum: | Basidiomycota |
Class: | Agaricomycetes |
Subclass: | Phallomycetidae |
Order: | Geastrales |
Family: | Geastraceae |
Genus: |
Sphaerobolus Tode (1790) |
Species | |
Geml, D.D. Davis & Geiser (2005) S. stellatus Tode (1790) |
Sphaerobolus is a genus of fungi in the family Geastraceae. Commonly known as the "cannonball fungi", species discharge their spores with explosive force. Discharged spore sacs are sticky and have a tendency to strongly adhere to whatever surface they encounter, making them a nuisance to homeowners, pressure washing contractors, landscape mulch producers and insurance companies.
The generic name is derived from the Greek words sphaer, meaning "sphere", and obolus, meaning "to throw". Sphaerobolus was first described by the Italian priest and biologist Pier Antonio Micheli (as Carpobolus) in 1729. Formerly, the genus was formerly placed either in its own family, the Sphaerobolaceae, in the order Sclerodermatales, or, more commonly, in the order Nidulariales. Currently, the genus is placed in the family Geastraceae.
Recent phylogenetic analysis suggests that Sphaerobolus should be placed in the gomphoid-phalloid clade along with related genera like Geastrum, Phallus, Pseudocolus, Ramaria, Clavariadelphus, Gomphus and Gautieria. Within the genus, three highly supported clades may be discerned, corresponding to S. stellatus, S. iowensis, and the recently described taxon S. ingoldii.
Fruiting bodies, which grow in groups, are 1–3 mm in diameter, roughly spherical or ovoid in shape, and white to buff in color. The peridium (outer wall) consists of several layers, including a gelatinous layer. At maturity, the exoperidium (outermost layer) splits into several lobes to expose the dark brown, single peridiole (spore casing). The peridiole is forcibly ejected (sometimes up to several feet), leaving an endoperidium. Spores are typically 6–10 x 4–6 µm, elliptical to oblong in shape, thick-walled, and hyaline. Species have a cosmopolitan distribution, and are usually found on dung, decaying wood (such as landscaping mulch), or vegetative litter.