HOW TO KNOW THE SEAWEEDS 



85a Thallus a simple sac to 3 cm. in diameter. Figs. 121, 122 



86 



85b Thallus not a simple sac 



87 



88a Plant saxicolous. Fig. 121 Halosaccion glandiiorme 



Fig. 121. Halosaccion glandiiorme (Gmelin) 

 Ruprecht. 



An entire medium size plant, X O-^S. Com- 

 mon on rocks along the Pacific Coast except 

 in southern CaUfornia. The large finger- 

 shaped sack is filled with water when the 

 plants are young and intact. When com- 

 pressed, however, the water spurts out from 

 microscopic openings near the tip in a num- 

 ber of very fine jets. Old plants become 

 eroded and the sack more or less filled with 

 sand. This curious alga, described from Kam- 

 schatka in 1768, was one of the first sea- 

 weeds recorded in the scientific literature from 

 the North Pacific. 



Figure 121 



92 



