Growth in Some Laminariaceae 



Annie L. Fallis, 

 University of Washington, Seattle. 



In a previous paper the writer (1) gave the results of observations 

 on the growth of the blades of Nereocystis. This paper is the result chiefly 

 of the extension of those observations to other members of the Lamin- 

 ariaceae. The work was done during the summer of 1915 at the Puget 

 Sound Marine Station at Friday Harbor, Washington. Observations were 

 made on the growth of the blades in length and breadth, elongation of the 

 stipes, and any peculiarities of growth of either stipes or blades. Experi- 

 ments were carried on with nearly two hundred plants of Laminaria sac- 

 charina (L.) Lam., Laminaria hullata Kjell., Costaria costata (Turn.) 

 Saund., Agarum fimbriatum Harv., Cymathere triplicata (P. & R.) J. Ag., 

 Egregia mensiesii (Turn.) Aresch., Nereocystis luetkeana (Mert.) P. & R. 

 and Alaria cordata Tild. 



Very little literature bearing directly on the growth of the kelps has 

 come under the observation of the writer. Setchell (2) in his work on re- 

 generation among kelps distinguishes three form of regeneration, viz. con- 

 tinuous physiological, periodic, restorative. His statements and figures 

 are, however, entirely the result of observation on plants as he found them. 

 He states that in all cases noted the regeneration proceeds only from the 

 stipe, that in no case did restorative regeneration originate in the blade. 

 In another paper Setchell (3) also refers to the increase in length of the 

 blade at the base at the same time that the stipe is increasing at the upper 

 end. Olga MUller (4) says the region of growth of Laminaria is at the 

 point where the stipe joins the blade. Ramaley (5) states that the grow- 

 ing region of Egregia is situated at the base of the blade, and that the 

 blade grows but very little after the stipe has attained a length of one 

 meter. In this paper Ramaley (5) homologizes the parts of Egregia men- 

 ziesii with those of other members of the Laminariaceae. Referring to 

 Egregia he says: "Both rachis and lamina increase in length but the lamina 

 commonly attains a length of only 3 to 5 dm., wliile the rachis may become 

 very long. Some plants collected in the month of July were 6 to 8 meters 

 in length." Yendo (6) discusses growth in length of Costaria, Vndaria, 

 and Laminaria , giving the general regions of greatest growth. 



Experience with Nereocystis led the writer to believe that most of the 

 work might be done from a raft. To test this plants of Costaria and of 



(137) 



