37S CRYPTOGAMIA. 



alone. Hence those genera, though more technicaT, 

 are less natural than Hoffmann's ; but they will, most 

 likely, prove the foundation of all that can in future 

 be done on the subject, and the works of Acharius 

 form a new jera in cryptogamic botany. It is only 

 perhaps to be regretted that he has been somewhat 

 too prodigal of new terms, which when not wanted 

 are always a burthen to science, and rather obscure 

 than illustrate it. Thus Hedwig used the term spo- 

 rangium iov <i secd-vtsstl, pericarpiumy in which the 

 learner would seek in vain for any distinction, or new 

 idea. A student might very justly 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 family. I would gladly therefore 

 retain the word J}'ons in preference to the thallus of 

 Acharius, receptaculum for his apothecium, pedicellus 

 for his hacillum or podetium, and seniina for his spora^ 

 because I see no improvement in the change. When 

 this or any other writer strikes out new ideas, and dis- 

 criminates parts hitherto mistaken or unknown, wc 

 thankfully receive from him new terms to express his 

 discoveries. Thus the cyphella of Acharius is a pe- 

 culiar sort of pit or pore on the under side of the 

 frond in that section of Lichens called Sficta, see 

 Engl. Bot. t. 1103, 1104 ; his lirell^ are the black 

 letter-like receptacles of the genus Opegrapha^ t, 

 1753 — 1756 ; his trica the analogous parts, resemb- 

 ling a coiled horse-hair, in Gyrophola, the Umbilwaria 

 of Hoffmann, t. 522. These terms are necessary 



