A sample of Scleroderma polyrhizon (also know as Scleroderma geaster) was recently submitted to the Plant Disease Clinic from Shelby County. The homeowner found scattered groups of the fungus in her lawn.

Scleroderma species also are known as hard puffballs or earth balls. The fruiting body of Scleroderma polyrhizon is round, usually about the size of a tennis ball or a baseball. The outer covering is thick, rough, and yellowish tan to brown. When mature, the puffball splits open into irregular sections, exposing dark brown to black powdery spores.

Scleroderma polyrhizon usually is partially buried in the ground. When it opens at maturity, it creates somewhat circular depressions in the ground. Such depressions may be considered a nuisance on highly manicured lawns. Scleroderma polyrhizon also can be found on sandy soil, ditches, and under hardwoods. Photos of Scleroderma polyrhizon can be found on the Iowa State University Plant Disease Clinic website :

An excellent book that pictures and describes mushrooms and fungi found in Iowa is Mushrooms Other Fungi of the Midcontinental United States by D.M Huffman, L.H. Tiffany, and G. Knaphus. It's published through Iowa State University Press, Ames, IA 50010.

Two Iowa State University bulletins also are available that describe mushrooms and other fungi found in Iowa:

• NCR 129 Mushrooms and Other Related Fungi
• Pm-1204 Morels, False Morels, and Other Cup Fungi

These bulletins are available from your local county extension office or from the Iowa State University Extension Distribution Center. Contact the Distribution Center at: 119 Printing and Publications Building Iowa State University Ames, Iowa 50011-3171 Telephone: (515) 294-5247 Fax: (515) 294-2945

This article originally appeared in the April 12, 2002 issue, p. 42.