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Puget Sound Marine Sta. Pub. 



Vol. 1, No. 3 



was whipped to pieces by wave action. The second showed an inch of 

 growth in the 3 ft. section and only one-half an inch in the remaining 

 portion. There again what growth there was is shown to be mostly in 

 the first three feet below the base of the laminae. As in the case of the 

 corked spcimens, decomposition was very evident, especially in the interior 

 of the uncorked kelps. 



The third experiment of this last group was of more importance. 

 Very slight notches were cut at 2 ft. intervals, beginning at the base 

 of the laminae and extending to the holdfasts. The results noted three 

 weeks later are given in Table 2. 



Table 2. Shorting the Growth in Different Parts of the Stipe, from the 



Laminae down 



From the above table it can be seen that the growing region is scat- 

 tered from the bulb to the holdfast. The greatest growth by far is in the 

 lower portion of the hollow part of the stem, while neither the bulb end 

 nor the solid holdfast end grow rapidly. 



The above results concerning the growth of kelp have all been based 

 on plants whose laminae have reached the surface. In the spring and 

 summer of 1915, the writer expects to work on kelps that have not as yet 

 reached the surface and thus secure accurate data for checking the general 

 observations made by Frye. 



Summary 



1. The stipe grows about the same when loose as when attached. 



2. The greatest region of growth of the stipe in fairly mature plants 

 is 2 to 4 feet below the laminae, the rate decreasing toward the ends. 



3. The rate of growth of the stipes measured was in July about 

 1 inch per day. 



4. Cut stipes usually die from decomposition, apparently due to the 

 action of organisms at the cut surface or on the interior of the hollow. 



