THALLOGENS. 103 



number of asci, or spore-cases, arranged vertically among 

 filaments which are termed paraphyses. The fecundating 



a b f g d e c 



FIG. 37. Lichens, a. Cladonia, with scarlet conceptacles. b. Usnea. c. Sticta. 

 d. Parmelia. e. Vertical section of receptacle, f. Same highly magnified, with thecse 

 and paraphyses. g. Double spore. 



apparatus is called the Spermogonia, and consists of small 

 rounded or oblong organs, lodged in particular tubercles 

 or immersed in the superficial layers of the thallus. The 

 cellular filaments of the spermagonia give off minute 

 oval bodies, called spfrmatia, which are analogous to the 

 antherozoids of Algae, but differ in being destitute of 

 spontaneous motion. 



7. The FUNGI form an extensive class of primitive 

 organisms, generally ranked as plants, but which have 

 so many peculiarities as to entitle them to be considered 

 apart. We should not greatly err if we regard them 

 as a third type of living things, differing both from ani- 

 mals and vegetables. They have no chlorophyll, as green 

 vegetables have, and which enables them to break up 

 carbonic acid. (Chap. VI, Sec. 2.) Light is not essen- 

 tial to the activity of Fungi, as it is to that of vegeta- 

 bles. They are incapable of assimilating inorganic food, 

 but live upon organic substances. They are the agents 

 of fermentation and of putrefaction, and their principal 



