270 INTRODUCTION TO CKYPTOGAMIC BOTANY. 



272. The distinguishing feature in these orders, which 

 are for the most part perfectly natural, is the predominance 

 of the organ from whence the names are taken. Thus, 

 in the first we have in various forms, from that of a cylinder 

 to a wide sac, the ascus or fertile cell, producing one, four, 

 eight, sixteen, or an indefinite number of sporidia from its 

 protoplasm. In the second the origin of the fructification 

 from the protoplasm is less clear. In some it seems to be 

 developed from the tip of the thread which penetrates into 

 the sac or bladder, which constitutes the envelope of the 

 fruit. In the third the Hypha, or mould-like mass of threads, 

 is the predominant feature ; while in the fourth the threads are 

 only rudimentary, and the spores either very large or very 

 numerous. In the fifth the leading feature is the Uterus or 

 general envelope of the sporiferous Hymenium ; while in the 

 sixth the Hymeniwm itself is predominant and generally naked, 

 but if covered with a general volva, the covering bursts either 

 just at the maturity of the Hymenium, or while the greater 

 part of the spore-bearing cells are yet imperfect. Their lead- 

 ing features, therefore, may be given after the fashion of Fries 

 in a single word : 



1. Ascus. 



2. Vesica. 



3. Hypha. 

 4 Sporce. 

 6. Uterus. 



6. Hymenium. 



I. AscoMYCETES, Bcrlc. (Endoth^ques, L4v.) 

 Sporidia definite or indefinite, produced from the proto- 

 plasm of elongated or dilated cells. 



273. The essential character of this important division con- 

 sists in the development of definite or indefinite sporidia 

 within certain of the external cells of the hymenium called 

 asci, which are frequently accompanied by inarticulate or sep- 

 tate, simple or branched, threads, which are abortive asci, 

 known under the name of paraphyses. 



274. There is always something in the shape of a cellular 

 stratum, which produces the asci and paraphyses, and this is 



