SCLERODERMA VULGARE AND ITS IOWA ALLIES 411 



SCLERODERMA VULGARE AND ITS IOWA ALLIES. 

 GUY WEST WILSON. 



The Sclerodermitaceae, or so-called hard puffballs, have been 

 very inadequately studied by American mycologists. Tndeed it 

 has been too common a custom to group all the material together* 

 as Scleroderma vulgare Hornem, without regard to external 

 markings, the thickness of the periderm, or the mode of rupture 

 for spore dispersal. Probably one of the most comprehensive 

 treatments of the American forms is that by Lloyd 1 in connection 

 with his studies on Australian species. His treatment has been 

 followed with some variations by Hard 2 and by Mcllvane 3 , each 

 adding variations to the treatment of species. Several of the 

 eastern forms have ben figured by Murrill in Mycologia. How- 

 ever, no systematic account of the American forms has come to 

 the notice of the writer. 



As treated by Ed. Fischer 4 the American members of the family 

 fall under three genera, Scleroderma, Pisolifhus, and Sclerang- 

 ium. Of these the first and second rupture irregularly for the 

 dispersal of the spores, while in the third the periderm breaks 

 into stellate lobes as in Geaster. Usually the spore mass is ex- 

 posed directly, but occasionally specimens arc found with a very 

 delicate and evanescent inner periderm. In Scleroderma the 

 periderm varies in thickness in different species but it is always 

 more permanent than in Pisolithus. The hynienial, (glebal) 

 characters are also of considerable interest and subject to a wide 

 range of variability. At first the hymenial surface is broken up 

 into a series of closed chambers which are irregulary disposed 

 among the sterile tissues of the sporophore. In Scleroderma 

 these lose their individuality with the maturity of the sporophore, 

 although they frequently remain as distinct lines of hyphae which 

 gives the spore mass the appearance of being contained in num- 

 erous small pockets. In Pisolithus these chambers are persistent 

 in the mature sporophore as peridioles quite similar in appear- 



a Tlie Lycoperdonacese of Australia, New Zealand and neighboring islands, 

 1905. pp. 12-15, pi. 29-31. 



2 The Mushroom, 1908, pp. 555-558. 567. 



3 One Thousand American Fungi, Revised edition. 1912, pp. 615-618. 



♦Engler & Prantl, Naturl. Pflanzenfam., 1899-1900, l 1 ** : 334-338. 



