RED ALGjS. 227 



sheeny, or iridescent, in the water, and are some- 

 times among the most- beautiful plants to be found 

 growing in the tide pools, especially when the sun 

 shines upon them. It turns much darker, and does 

 not adhere to paper, in drying. Its geographical 

 range is from the Carolinas north, on the east coast. 

 .It is not found on the Pacific side of the conti- 

 nent, though two other species of the genus, which 

 I have not thought it best to give an account of, 

 do occur there, viz. : C. canaliculatus and C. affinis, 

 the latter of which. Dr. Farlow thinks, may be a 

 variety of the former. 



Qenus.—IRW^A* Bory. 



iRIDiEA LAMINARIOIDES, BoRY. 



This species sufficiently characterizes the genus. 

 It has a large, wide, thick, membraneous frond, aris- 

 ing from a stalk two inches long, which is at first 

 cylindrical and then flattened. The frond is usually 

 simple, though sometimes lobed ; from one to two 

 feet long and from one to three inches wide, smooth 

 when barren, warty when bearing the true firuit, and 



* Iridxa ^ Many colors. 



