ORDER HYMENOGASTRALES 



541 



Fig. 174. Hyraenogastrales, Family Secotiaceae. Secotium erythrocephalum Tul. 

 (A) Mature plants. (B) Section of tramal plate. (C, D) Vertical sections through young 

 and nearly mature plants. (Courtesy, Cunningham: Brit. Mycol. Soc. Trans., 10:216- 

 224.) 



cavities. Apparently within the main tissues of the pileus other hymenial 

 cavities develop as well as in the thick tramal plates in the gleba so that 

 finally the latter is made up of very many narrow, hymenium-lined cav- 

 ities, separated by thin tramal plates. As the stipe elongates the edge of 

 the pileus pulls loose from it and the gleba becomes partly exposed to the 

 air. Since the glebal cavities are not continuous the spores are distributed 

 by the action of insects infesting the spore fruits and also by the decay of 

 the latter. The presence of cystidia in some species of Secotium is another 

 point of similarity to the Agaricaceae. There are some very small species, 

 e.g., S. coprinoides Routien (1940), about 4 mm. tall with a pileus about 

 2 mm. broad. Its gleba consists of numerous (about 18) radial hymenial 

 cavities extending from the lateral peridium to the stipe. The hymenium 

 consists of two- or four-spored basidia intermixed with paraphyses. The 

 ellipsoidal spores are smooth, black, and with a short pedicel formed by 

 the apical portion of the sterigma. S. olbium Tul. is 4 to 6 mm. tall but 

 the spores are smaller, spherical, and wrinkled. The structure of the gleba 

 of the former is somewhat similar to that of Gasterellopsis, but is not some- 

 times unilocular and the spores are of different types. There is no deli- 

 quescence so that this is not a Coprinus and the position of the spore on 

 the sterigma is typical of the Gasteromyceteae. At maturity the edge of 



