CRYPTOGAMIA. ^'i'7 



Thus Hedwig used the term sporangium for a seed- 

 vessel, perkarpiam, in which the learner would 

 seek in vain for any distinction, or nesv idea. A 

 student might very jusdy complain if, in a science 

 necessarily so overburthened with words, he were 

 required to call the same part by a different name 

 in every different fan)ily. I would gladly therefore 

 retain the word frons in preference to the thalliis 

 of Acharius, receptaculum for his apothecium^ pedi- 

 cdlus for his bacillum or podetium, and semina for 

 his sporct, because I see no improvement in the 

 change. When this or anv other v»riter strikes out 

 new ideas, and discriniinatcs parts hitherto mistaken 

 or unknown, we thankfully receive from him new 

 terms to express his discoveries. Thus the ajphella 

 of Acharius is a peculiar sort of pit or pore, on the 

 under side of the frond, in that section of Lichens 

 called Stkta, see Engl. Bot. t. 1103, 1104; his 

 Urellce are the black letter-like rece})tacles of the 

 gGim?> Ope gr up Jut, t, 17.53 — M56', his /;7V<^ the 

 analogous parts, resembling a coiled horse-hair, in 

 Gyrophora, the Umbilkarki of Hoffmann, t. 522. 

 These terms are necessary and instructive, and are 

 chosen with that accuracy and taste for which Dr. 

 Acharius i;^ conspicuous. 



The aquatic or submersed \^^4j<^ form a distinct 

 and peculiar tribe. Some of these abound in fresh 

 water, others in the sea, whence the latter are com- 

 monlv denominated sea-weeds. The chief ijenera 



