PEZIZALES 



327 



In the course of the further development, the fertile portion becomes 

 increasingly separated from the sterile and changes to pileate head; this 

 head is fertile only on its upper side, however, while the lower remains 

 sterile. The forms with the originally clavate fructifications are united 

 in the subfamily Geoglosseae, those with capitate fructifications in the 

 Cudonieae. Their classification rests on the special differentiation of 

 these fructifications and on the form of the ascospores and paraphyses. 

 To the Geoglosseae belong Mitrula, Microglossum, Geoglossum, Gloeoglos- 

 sum Trichoglossum and Spathularia; to 

 the Cudonieae, Leotia and Cudonia (Dur- 

 and, 1908). 



As far as the ontogeny of the Geo- 

 glossaceae has been studied, about one- 

 half the forms correspond to the normal 

 hemiangiocarpous type, the other half 

 to the purely gymnocarpous. To the 

 former there belong Spathularia velutipes, 

 Cudonia lutea, Microglossum viride (Duff, 

 1920, 1922) and Mitrula paludosa (M. 

 phalloides) (Dittrich, 1902). To the 

 second group belong Trichoglossum 

 hirsutum, T. velutipes, Geoglossum glab- 

 rum and Gloeoglossum difforme (Duff, 

 1920, 1922). While the hemiangiocar- 

 pous type includes all possible forms, the 

 gymnocarpous forms are closely related 

 and grouped around Geoglossum. 



In youth, the fructifications of both 

 groups seem identical. They arise as a 

 tangle of closely twined hyphae which are elongate at the periphery 

 and entirely surround the tangle. In the middle of the base, however, 

 they are more rounded or polyhedral. The middle cells elongate 

 upwards and thus cause the elongation of the whole fructification, 

 while the basal cells remain irregularly angular with thickened walls. 

 In the hemiangiocarpous group the peripheral hyphae, six to eight cell 

 layers deep, gelify and surround the whole fructification in a gelatinous 

 sheath which in systematic literature is called veil or volva; it corresponds 

 to the velum universale of the Agaricales {mutatis mutandis). In most 

 forms it remains one layered; in Spathularia velutipes it divides into a 

 compact, thin-walled, inner and a loose, thick-walled, outer layer. In 

 the gymnocarpous group, there is no differentiation of a special sheath 

 layer and the fructification is open throughout its whole development. 



In the apical parts of the fructification, the hyphae underneath (or 

 in the gymnocarpous forms, those directly under the surface) become 



Fig. 217. — Gloeoglossum glutinosum. 

 (Natural size; after Falck, 1916.) 



