HOW TO KNOW THE SEAWEEDS 



130b Blades brownish, with five percurrent ribs. Fig. 170 



Costaria costaia 



Fig. 170. Costaiia costata (Tur- 

 ner) Saunders 



The lower part of a relatively- 

 small plant showing the holdfast 

 of branched hapteres, the simple 

 stipe and the five prominent ribs 

 of the blade, three on one side 

 and two on the other, X 0.7. This 

 species is variable in size and 

 shape. It may reach a height of 

 two meters and a breadth of 30 

 cm., the blade being either ovate 

 or narrowly lanceolate. It may he 

 found on rocks, wood, or other 

 large algae in the lower inter- 

 tidal and upper infratidal regions 

 along the whole Pacific Coast 

 from the Bering Sea to southern 

 California. In the southernmost 

 part of the range, however, plants 

 are usually confined to moderate- 

 ly deep water. The mature blades 

 fruit from midsummer until late 

 in the fall, the sporangial sori 

 largely covering the bullate, or 

 blistered portions of the surface. 



Figure 170 



There has long been a difference of opinion among phychologists 

 as to the number of species of Costaria that should be recognized. 

 The members of the genus as they are now known are confined to the 

 North Pacific Ocean. Four species and one variety have been referred 

 to Costaria on our North American Coast from one time to another, 

 but Setchell and Gardner in their 1925 monograph concluded that only 

 one exceedingly variable species, namely, C. costata, is present in 

 this area. More recently the Japqtnese have reached the same con- 

 clusion for their plants on the western side of the North Pacific. 



129 



