388 INTRODUCTION TO CRYPTOGAMIC BOTANY. 



found T. ■nadreporiforme in New Zealand. An obscure species, 

 however, of this genus (as it seems) occurs at the Cape of 

 Good Hope {T. bicolor, Taylor). Another example is afforded 

 by the genus Myriangium, Berk, and Mont. It was first 

 found under two forms by Mr. Drummond, in Australia. One 

 of these, on communication with Dr. Montague, proved to be 

 identical with a Lichen from Algiers and the south of France, 

 and has since been found to ascend as far north as the Channel 

 Islands. It occurs also in New Zealand ; and a far handsomer 

 species than either has been found in South Carolina by Dr. 

 Curtis. With such facts as these before us, we cannot venture 

 to do more than say positively that this or that genus is a cha- 

 racteristic of the Flora of this or that region, or that such and 

 such genera scarcely reach such and such regions, and all our 

 future remarks are to be understood with the limitations above 

 indicated. We shall in the sequel point out the principal seats 

 of the genera of Lichens according to their tribes, without 

 descending to the species. The distribution of a large number 

 of species has been worked out by Mr. Babington in Dr. 

 Hooker's Flora of New Zealand, and that of some others in 

 Seeman's Botany of the Herald, to which the reader is re- 

 ferred ; he wdll also find a good deal of information made 

 ready to hand by Eschweiler, respecting the distribution of 

 the Brazilian Lichens in Martins' Flora of Brazil. We shall 

 follow the arrangement of the Lichens given by Dr. Montague 

 in his Aper(ju Morphologique de la Famille des Lichens, pub- 

 lished in the Diet. Univ. d'Hist. Nat., Paris, 1846, which is 

 based upon that of Fries, and which appears, upon the whole, 

 the most satisfactory that has been proposed. Lichens are 

 divided naturally into two divisions of very different statistical 

 importance ; in one of which the hymenial disc is ultimately 

 open ; in the other, on the contrary, remains permanently 

 closed. The former of these, as displaying an hymenium like 

 that of Peziza, may be considered the most perfect ; the other 

 approximates very closely to Sphceria. 



