78 FUNGI. 



hymenium soon becomes exposed. In some instances, there is 

 a close affinity with the Elvellacei, the exposed hymenium being 

 similar in structure, but in all the disc is at first closed. In 

 orbicular forms, the fissure takes place in a stellate manner from 

 the centre, and the teeth are reflexed. In the Hysteriacei, where 

 the perithecia are elongated, the fissure takes place throughout 

 their length. As a rule, the sporidia are more elongated, more 

 commonly septate, and more usually coloured, than in Elvellacei. 

 Only a few solitary instances occur of individual species that 

 are parasitic on living plants. 



In the Spliceriacei, the substance of the stroma (when pre- 

 sent) and of the perithecia is vari- 

 able, being between fleshy and waxy 

 in Nectriei, and tough, horny, some- 

 times brittle, in Hypoxylon. A peri- 

 thecium, or cell excavated in the 

 stroma which fulfils the functions of 

 a perithecium, is always present. 

 The hymenium lines the inner walls 

 of the perithecium, and forms a gela- 



FIG. 42. Spkcena aquila. . ' 



tinous nucleus, consisting of asci and 



paraphyses. When fully mature, the asci are ruptured and the 

 sporidia escape by a pore which occupies the apex of the peri- 

 thecium. Sometimes the perithecia are solitary or scattered, and 

 sometimes gregarious, whilst in other instances they are closely 

 aggregated and immersed in a stroma of variable size and form. 

 Conidia, spermatia, pycnidia, &c., have been traced to and asso- 

 ciated with some species, but the history of others is still obscure. 

 Many of the coniomycetous forms grouped under the Sphceronemei 

 are probably conditions of the SpJitBriacei, as are also the Melan- 

 comet, and some of the Hypliomycetes. A very common fungus, 

 for instance, which is abundant on sticks and twigs, forming 

 rosy or reddish pustules the size of a millet seed, formerly 

 named Tubercularia vulgaris, is known to be the conidia-bearing 

 stroma of the sphasriaceous fungus, Nectria cinnabarina ; * and so 



* "A Currant Twig and Something on it," in "Gardener's Chronicle " for 

 January 28, 1871. 



