318 Puget Sound Marine Sta. Pub. Vol. 1, No. 27 



lands, it seems probable that the increased light available due to the removal 

 of the dense mat of older kelps resulted in increasing the growth of young 

 plants below, whose growth had formerly been inhibited by lack of light. 

 In harvesting Macrocystis, a perennial kelp on the California coast, it 

 has been reported that a new growth of kelp appears at the surface in 

 the cut areas within a short time. This is explained as due to the "stooling 

 cut" of the plants from the base.^* The California cases and those in the 

 Queen Charlotte Islands, while appearing superficially alike, are thus evi- 

 dently due to very different causes. 



No cause for the spiral form and the accompanying roughening of 

 kelps seems evident. It is true, of course, that kelps growing in large 

 clusters are commonly twisted together and many of these show a some- 

 Avhat spiral form, but the spiral in these cases shows few turns and no 

 roughening corresponding to the spiral. There does not seem to be any 

 evidence that the roughened spirals observed are due to the kelps twining 

 about any object. Mechanical injury and the presence of organisms seem 

 to be likewise difficult to establish as causes. 



The kelp bed that has been made the basis of this study is not a 

 large one as compared with many others of the region. Neither do the 

 individual kelps in it reach any more than average size. This bed was 

 selected for study because its location made it possible for the writer to 

 visit it conveniently at different seasons. It is fairly representative of aver- 

 age conditions. In general, larger beds and more vigorous kelps are found 

 m the rougher waters that communicate more directly with the Strait of 

 Juan de Fuca. 



i4Cameron, F. K. Pacific kelp beds as a source of potassium salts. Kept. 

 No. 100. U. S. Dept. Agric, p. 15. 1915. 



