346 Puget Sound Marine Sta. Pub. Vol. 1, No. 29 



On account of the lack of change in the number and condition of the 

 plants at Lincoln Beach from November 10 on through the winter, it was 

 thought possible that the change of season might have no effect on the algal 

 vegetation of Puget Sound; but with the advent of spring, changes were 

 apparent in the condition of some species, which show that there are 

 seasonal periods in at least some of the algae here. The most striking 

 change was in the appearance or increased number of young plants, indi- 

 cating a renewal of growth. The greater number of species found had 

 young plants coming up near the older plants all winter long (tables 1 

 and 2). Other plants, notably the Laminariaceae, were either not found 

 at all during the winter, or else were old and battered. Rigg (1917) has 

 recorded the condition of Nereocystis in winter. His conclusions concern- 

 ing the plant's seasonal periodicity and the appearance of the young plants 

 in early spring are confirmed by my observations that j^oung plants al- 

 though not found at all during the winter were quite common in March and 

 April. The same is true of Costaria costata, Laminaria hullata and Lami- 

 naria saccharine. On March 25 these young Laminariaceae were under six 

 inches, in April they were mostly considerably more than 6 inches long. 

 By April, young plants of Scytosiphon, Phyllitis and Punctaria were rare, 

 these species starting to grow in February. Since the change in the tem- 

 perature of the water is so slight at the depth at which Nereocystis grows, 

 it seems probable that light intensity is responsible for its periodicity. 



Although no Soranthera was found during the winter, young plants 

 from the size of a pinhead to the size of a marble were abundant on April 

 22. Occasional plants were reproducing. In Iridaeo, Prionitis, Gigartina 

 mamillosa, Fucus and Ulvo, an increase in the number of young plants was 

 noticeable in March, although young ones had been more or less common 

 all winter. 



Fucus has a very evident periodicity. Scattered plants were found all 

 winter. Their persistence from the previous season was evident from their 

 coriaceous texture and dark color. The ends of the branches remained 

 flat and leafy until the end of January or the first of February, showing 

 no sign of the receptacles so characteristic of the plant in summer time. On 

 P'ebruary 4 the branches were still flat, but with the ends dotted with 

 young conceptacles. On February 24 the ends had become distinctly swol- 

 len but were still light colored and young. These scattered plants are 

 evidently stray ones which failed to complete their growth in the normal 

 period; for the rocks were covered with young plants in March, and these 

 were reproducing abundantly by summer. 



Rhodymenia pertusa was not found reproducing during the winter 

 but on April 22 all of the half dozen specimens found were dotted with 

 young cystocarps or tetrasporangia. 



