GASTEROMTCETEAE 531 



cases (chiastobasidial) but is sometimes longitudinal (stichobasidial), e.g., 

 in Tulostoma. In some cases subsequent divisions produce eight nuclei or 

 even more. Usually the number of basidiospores is four, but not rarely six 

 to eight and in rare cases up to 12 spores are produced. These are almost 

 always at first uninucleate but in most of the few cases studied they early 

 become binucleate by the division of the original nucleus. Whether such 

 binucleate spores give rise to the dicaryon phase of mycelium is not 

 proved, but seems probable. Lorenz (1933) has shown that in Sphaeroholus 

 grandis Lorenz the uninucleate basidiospores give rise to monocaryon 

 mycelia. These mycelia show two sexual phases, i.e., this species is sexu- 

 ally bipolar, and only when the appropriate mycelia are mated does a 

 dicaryon mycelium with clamp connections arise. In this species the 

 basidiospores are uninucleate, although some species of this genus have 

 been described as producing binucleate spores. Crucihulum vulgare Tul, 

 and Cyathus striatus (Willd.) Pers. are both, according to Nils Fries 

 (1936), quadripolar. 



In general the structure of the spore fruit in the Gasteromyceteae is as 

 follows: Externally there is a peridium consisting of one or more layers. It 

 may be firm and hard {Scleroderma) or soft and papery or may even dis- 

 appear during the development of the spore fruit, in Gautieria graveolens 

 Vittad., being present, according to Fitzpatrick (1913), only in the very 

 young stages. Within the peridium the tissue may consist simply of the 

 gleba or of the gleba traversed by "veins" or by a "columella" or by both. 

 The gleba consists of a more or less fleshy mycelial growth containing 

 usually numerous hymenium-lined cavities (hymemal cavities) but only 

 one in a few cases. The columella and veins are slender or stout strands of 

 hyphae having several functions, food conduction, support, and in some 

 cases the dehiscence of the spore fruit at maturity. The gleba in many 

 genera undergoes autodigestion after the basidiospores have been formed. 

 The tissues involved are the basidia and the fungous tissue lying between 

 the hymenial cavities, the trama. As a result nothing may be left of the 

 gleba except the basidiospores, and in a few cases the basidia also, or also 

 a few stiff threads, the capillitium. These are simple or branching thick- 

 walled hyphae, which develop in the interhymenial tissues of the gleba 

 before maturity of the spore fruit. They are rarely septate. The tangled 

 mass of capillitial hyphae prevents the escape of all the spores at once, 

 permitting them to sift out a few at a time. In some cases hymenial 

 cavities with a definite layer of hymenium are wanting but clusters of 

 basidia appear here and there in the gleba. 



The ontogeny of the spore fruit exhibits an early gymnocarpic stage in 

 some species while in others the earliest stages are angiocarpic. The gym- 

 nocarpic stage usually becomes closed early so that the development cor- 

 responds to the pseudoangiocarpic mode of growth found in various 



