286 Mr George Traill on the 



76. Fucus serratus, Linn. 



Common on rocks at about half-tide level. Perennial. Left 

 uncovered by the tide, and exposed to the light for some hours 

 daily. Fruit best in winter. 



77. Fucus vesiculosus, Linn. 



Common on rocks between tide marks. Left uncovered by the 

 tide, and exposed to the light for some hours daily. Perennial. 

 Fruit in winter and summer. Host plants : Cladostephus spongiostis, 

 Chondnis crispus. 



PELVETIA, Dene. 



78. Pelvetia canaliculata (Linn.), Dene and Thur. {Fucodium canali- 



culatum, J. Ag. ) {Fucus canaliculatus, Harv. ) 



Common on rocks between half-tide level and high-water mark. 

 Left uncovered, by the tide, and exposed to the light for many 

 hours daily. Perennial. Fruit from June to September. 



ASCOPHYLLUM, Stackh. 



79. Ascophyllum nodosum (Linn.), Le Jolis. {Fucus noclosus, Linn.) 

 Common on rocks and boulders at about half-tide level Peren- 

 nial. Fruit from December to September. 



HIMANTHALIA, Lyngb. 



80. Himanthalia lorea (Linn.), Lyngb. 



On exposed rocks at about low-water mark. All the year. Fruit 

 in summer. Spores escape in August. 



Order VI.— DICTYOTEiE. 

 DICTYOTA, Lamoui. 



81. Dictyota dichotoma (Huds.), Lamour. 



In pools at low-water mark, and probably at a greater depth, east 

 of the old harbour; rather rare. (G. W. T. 1888.) Annual. 

 Summer. 



Class IV.— RHODOPHYCE^. 

 Order VII.— FLORIDE^. 



Family.— PORPHYRACEJi:. 



PORPHYBA, Ag. 



82. Porphyra laciniata (Ligbtf.), Ag, 



Common on exposed rocks, and epiphytic on Algse, usually 

 between half-tide level and high-water mark. Left uncovered by 

 the tide, and exposed to the light for many hours daily. All 

 the year. Fruit best in August and September. Host plants : 

 Corallina officinalis, Callithamnwn arlmscida, Himanthalia lorea. 



