INTHODUCTION TO CRYPTOGAMIC BOTANY. 



201 



southern hemisphere. Bostrychia vaga, in the cold cKmate of 

 Kerguelen's Land, may be traced from rocks and stones, about 

 high-water mark, to a considerable distance inland. The tips 

 of its threads are often curled, which makes them peculiarly- 

 apt to be entangled with other plants. Though Basya elegans 

 is equally common in America and southern Eiu-ope, while its 

 near relative, D. villosa, abounds in Van Diemen's LaOd, the 

 European D. coccinea is not known on the eastern North 

 American coast ; and its nearest ally is found on the Western 

 Pacific shores, at Puget's Island, from whence it was brought 

 by Captain Wilkes's expedition. Rytiphlcea is a rare inhabi- 

 tant of our southern coasts. The genera are far more abun- 

 dant in the southern than in the northern hemisphere. Eleven 

 genera only occur on the eastern coast of North America, 

 including Chondria, and some of them are sub-tropical, while 

 in the Southern Ocean there are at least twenty-three. 

 Amansia, Alsidium, Acanthophora, and Digenea, are 



Fig. 49. 



Polyzonia cuneifolia, Mont., with sticMdia, conceptacle, and spores, 

 magnified. From specimens commumcated by Dr. J. D. Hooker. 



unknown upon our coasts, and delight in a warm climate. 

 They occur, therefore, in such tracts as the Ked Sea; whUe, on 

 the contrary, Odonthalia is a genus of high latitudes. Though 

 so common in some parts of the Scottish coast, it is wholly 



