364 THE BASIDIOMYCETES 



Shantz, H. L., and R. L. Piemeisel, "Fungus fairy rings in eastern Colorado 



and their effect on vegetation," /. Agr. Research, 11: 191-245, 1917. 

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 Snell, W. H., "Tentative keys to the Boletaceae of the United States and 



Canada," Rhode Island Botan. Clnb Publ., 1. 25 pp. 1936. 

 Thomas, H. E., "Studies on Arviillaria mellea (Vahl.) Quel., infection, 



parasitism, and host resistance," /. Agr. Research, 48: 187-218, 1934. 

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My col., 21: 113-130, 1929. 

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conifers," Phytopathology, 1: 166-177, 1917. 

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Elisha Mitchell Set. Soc, 38: 127-137, 1922. 

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Mitchell Sci. Soc, 45: 130-135, 1929. 

 Yates, H. S., "The comparative histology of certain California Boletaceae," 



Univ. Calif. Publ. Bot., 6: 221-274, 1916. 

 Zeller, S. M., "The development of the carpophores of Ceriomyces zel- 



leri," Mycol., 5:235-239, 1914. 



GaSTROxMYCETES 



The Gastromycetes (Gasteromycetes) include those basidial 

 fungi having spores that are produced within closed basidio- 

 carps. Some have subterranean fructifications that emerge as 

 thev approach maturity; others remain underground; a third type 

 develops entirely aboveground. In some the basidiospores can 

 escape only after disintegration of the outer or peridial tissues, 

 and in others special means of dehiscence are provided. Some are 

 stalked, others sessile. The Gastromycetes include approximately 

 120 genera and 1200 species. 



The name Gastromycetes suggests the term pufTballs, which 

 is popularly applied to the fruit bodies of such typical ones as 

 species of Lycoperdon, Bovista, Geaster, Scleroderma, and Piso- 

 lithus. In general, the puffball or fruit body of members of this 

 order has the following course of development: Along the rhizo- 

 morphs (strands of compact, mycelial threads), which occur in 

 decaying stumps and logs or in leaf mold, small, white spherical 

 masses appear. As these enlarge, several regions become differen- 

 tiated. The outer portion is a peridium consisting of one or 

 more layers. At maturity the peridium of Lycoperdon and Bo- 

 vista is soft and papery, whereas in Scleroderma it is firm and 



