SCLERODERMATACEAE 



Plants more or less globular, usually partly or wholly exposed above ground at 

 maturity (but at times entirely embedded) ;* peridium thick or thin, tough or fragile 

 at maturity, rupturing irregularly and tardily, or splitting at maturity into stellate 

 lobes, or, in Pisolithus, flaking off in fragments from above downward; gleba divided 

 irregularly by thin or thick sterile tramal plates into areas which from the first are 

 stuffed full of the fertile tissue containing the irregularly arranged basidia. At maturity 

 both plates and fertile tissue break down into a powder at times by slow degrees. Plants 

 attached below by a thick mass of mycelial plates and fibers and sometimes stalked. 

 Basidia swollen, pyriform to subspherical; spores spherical, echinulate and sometimes 

 also reticulate, brown; capillitium none or rudimentary. 



A closely related family is Podaxaceae, a long-stalked group of large plants not 

 represented in eastern United States. Podaxon and Phellorina occur in the western 

 states. 



Key to the Genera 



Walls of the gleba chambers very thin and not forming distinctly outlined or complete chambers, dis- 

 organizing throughout at maturity, together with the fertile tissue, to form a flocculent or 

 powdery mass containing the spores Scleroderma 



Walls of the gleba chambers thick, forming distinct peridioles which slowly pulverize from above down- 

 ward after maturity and exposure Pisolithus 



SCLERODERMA Pers. 



Characters of the family and distinguished from Pisolithus by the absence of 

 distinct and persistent peridioles in the gleba. The plants are sessile except for a root- 

 like attachment of plates and fibers mixed with earth. The brownish or purplish or 

 olive-brown spores are echinulate or in several species obviously reticulated. In some 

 cases there is visible regularly or at times (before much exposure) a peculiar veil or halo 

 connecting the tips of the spines or reticulum. This effect is probably the result of a 

 hyaline material which covers the spore between the spines. The spores of this genus 

 show a remarkable peculiarity in their development. In 1889 it was shown by Beck 

 (1. c.) that in Phlyctospora fusca Corda (Scleroderma Juscum (Corda) E. Fischer) the 

 spores when somewhat more than half grown become surrounded by a sheath of cells 

 which grow in from surrounding hyphae or much less often from the basidia. This 

 sheath persists until the maturity of the spores and as the basidia have disappeared 

 when the sheath is formed, the remaining growth and maturation of the spores is made 

 possible by nourishment derived from the sheath. The sheath in most species is not 

 so prominent as in S. Juscum, but in essentials the development of the spores is the same 

 in all species investigated. We have studied S. lycoperdoides through these stages and 

 find that the basidia disappear when the spores are only half grown and quite colorless. 

 See details under that species. 



* Zeller has recently described a peculiar Scleroderma from Oregon that is normally quite subterranean and that is still 

 more remarkable in having a deliquescent gleba. (Mycologia 14: 193. 1922.) Scleroderma pteridis is also subterranean 

 (see p. 162). 



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