Fig. io6 Macrocystis pyrifera. A, entire plant (xio-)- B, young 

 plant ( X I). C, slightly older plant with primary slit and two 

 secondaries ( x \). D-F, schematic drawings showing branching. 

 G, shoot apex ( x |). H, mucilage duct ( x 200). I, 'sieve tube' and 

 plate with callus ( x 290). J, part of fertile blade (sori black) ( x \). 

 K, two paraphyses ( x 140). L, unilocular sporangium ( x 290), (A, 

 B, D-L, after Skottsbergj C, after Oltmanns). 



Lessoniaceae : Macrocystis {macro, large; cystis, bladder). Fig. 106 



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 



186 



