LAMINARIALES (HETEROGENERATAE) 183 



p. 275) of great interest. Local names employed for Pelagophycus 

 are elk-kelp, sea pumpkin and sea orange. 



Fig. 123. Nereocystis Luetkeana. A, young plant. B, mature plant. C, branching 

 from bladder. (After Oltmanns.) 



*Lessoniaceae : Macrocystis {macro, large; cystis, bladder). Fig. 

 124. 

 The perennial fronds of this giant of the ocean may reach 

 200 ft. in length, the alga growing at a depth of 20-30 m. in the 

 North and South Pacific Ocean and near the Cape of Good Hope, 

 all being regions where the temperature of the water ranges between 

 o and 20° C. In the juvenile plant the stipe is simple and solid, but 

 later on it branches one, two or three times in a dichotomous 

 fashion, although uhimately the branching becomes unilateral and 

 sympodial, each branch bearing tAvo to eight laminae. The main 



