INTRODUCTION TO CRYPTOGAMIC BOTANY. 



273 



of no practical importance, their greatest singularity being 

 their affecting animal substances, and their external resem- 

 blance to little puffballs, though differing greatly in structure. 

 In those Myxogastres, where a sort of ascus exists, the spores 

 arise from the sporophores, and not from the protoplasm. 



Fig. 62. 



a. Onygena equina, natural size. 



b. 0. corvina, vert, section. Magnified. 



c. 0. equina, asci and sporidia. Magnified. After Tulasne, 



d. Meliola amphitricha, asci and sporidia. Magnified. 



e. Meliola cymhisperma, Mont., sporidia. Magnified. Both from spe- 

 cimens in my herbarium. 



277. Asci have not always been found. Tulasne was the first 

 to point out their existence; but it is very possible tliat states 

 may occur in which no asci are developed, but in which they 

 are rej)laced by naked spores. The peridium often separates 

 from the included mass by a more or less regular fissure. 



2. Perisporiacei, Fi\ 



Perithecia free, astomous, at length dehiscent, often sur- 

 rounded by threads distinct from the mycelium (fulcra). Asci 

 tubular or saccate, often absorbed at an early stage, springing 

 from the base, occasionally solitary, 



278. The species of this group are distinguished by the 

 in general great development of the mycelium, their frequently 

 epiphytous habits, the thin brittle walls of the perithecia, and 



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