16 



Puget Sound Marine Sta. Pub. 



Vol. 1, No. 3 



caused this method to be abandoned. The intruding kelps were usually 

 twined so far below the surface that it was impossible to remove them. 



Finally, a large number of healthy Nereocystis plants were pulled 

 free from the rocks to which their holdfasts clung. Exact measurements 

 were taken of each, from the region on the bulb where the laminae arose, 

 to but not including the holdfast. Then these holdfasts were attached by 

 strips of cloth either to the lower portion of a raft which was anchored at 

 the edge of the kelp bed, or to the stipes of other individuals. Two 

 plants were raised from the water with their holdfasts carrying the rocks 

 to which they were attached. These, too, were measured for some time 

 and the rate of growth was found to be approximately the same as for 

 those torn loose, showing that anchoring the holdfasts did not affect the 

 growth. All the plants experimented on were measured at intervals of 

 two days, until they were broken off by wind and waves, or in some other 

 way destroyed. Most of the measurements were made on kelps which 

 had been anchored, since the inaccuracy in measuring fixed kelps was too 

 great. Table 1 gives the observations on the growth of fourteen healthy 

 specimens. 



Table 1. Showing Rate of Growth of Stipes 



Original length 

 of Stipe. 



No. of days 

 measured. 



1' 6" 



I'lO" 



5' 5" 

 ll'lO" 



13' 6" 



15' 0" 



18' 4" 



18' 7" 



20' 7" 

 21' 1/2' 



22' 7" 



25' 2" 



26' 6" 



27' 5" 



6 

 4 

 4 

 2 

 4 



12 

 4 



19 



4 

 12 

 20 



20 



From the table one can easily figure that the average growth of the 

 stipe per day is about 1 inch. 



The number of days each plant was measured varied for several 

 reasons: First, the kelps were often carried away by storms; second, 

 they suffered at the hands of persons passing in small boats ; third, some 

 became entangled and were drawn too far below the surface to be freed 

 without injury; fourth, at high tide some of the kelps would not reach 

 the surface and thus could not be measured; fifth, decomposition often 

 set in and destroyed them. This decomposition was often found to begin 

 in "sunburned" spots. 



