Vol. i No. 5 



TORREYA 



May, igoi 



A NOTE ON THE BLADDER KELP, NEREOCYSTIS 



LUTKEANA 



By W. A. Cannon 



One of the most interesting forms of the West Coast marine 

 algae is the bladder kelp {Nereocystis Lutkeana Post. & Rupr.). 

 This is closely related to the giant kelp (Macrocystis), to the sea 

 palm (Postelsia), to the devil's apron {Laminarid), and to other 

 forms which are familiar to all frequenters of the coast of middle 

 California. 



In these algae there is an interesting correlation between the 

 environment and the structure and certain other peculiarities of 

 the plants. They not only vary in the length of the daily ex- 

 posure to the air, but, in addition, they occupy a varying position 

 with regard to the impact of the waves. The bladder kelp is 

 normally never out of the water, while the sea palm is regularly 

 exposed to the drying influence of the atmosphere, and the other 

 kelps vary between these extremes. The different relation of 

 these forms to the waves, which will be spoken of later in this 

 sketch, is presumably the basal cause of a certain and unexpected 

 weakness of the stem of Nereocystis, as well as accounting for the 

 great mechanical strength of the stem of Postelsia. The exami- 

 nation of other kelps would undoubtedly disclose quite as remark- 

 able a connection between the plants and their individual sur- 

 roundings. 



The bladder kelp is light brown in color and somewhat trans- 

 lucent. It is said to reach a length of 300 feet and is therefore 

 to be reckoned as one of the largest marine plants. The blad- 



[The exact date of publication of each issue of Torreya is given in the suc- 

 ceeding number. Vol. 1, No. 4, comprising pages 37-48, was issued April 19, 1901.] 



