108 SEA MOSSES. 



and Mr. Collins and Mrs. Bray in Robinson's " List 

 of Essex Plants," report it from Gloucester. 



Castagnea virescens, Thuret. 



This is apparently a shorter but more robust - plant, 

 and more thickly branched than the last. It is of 

 a more pronounced green color, as its name implies. 

 It is not more than three inches long, main stem and 

 branches both straighter than in C. Zosterce, but 

 having the twiggy appearance peculiar to the genus. 

 American plants are said to grow on Zostera, though 

 no doubt it grows parasitical on the other Algae also. 

 According to Le Jolis they are found on stones and 

 pebbles, and in tide pools on the rocks at half tide, 

 toward the end of spring. Mrs. Davis finds it growing 

 on sand covered rocks at half tide, all summer at 

 Gloucester, and Mr. Collins found it in June at Revere, 

 cast up from deep water, not very common. Miss 

 Booth makes report of it in the same situations at 

 Peconic Bay. It is also reported at Wood's Holl and 

 Portland. I should expect to find it at Marblehead. 



