A Monograph of the Geniis Alaria. 55 



demarcation between the two parts is never difficult to recognize. 

 The illustrations of the Greenland specimens given by Eosenvenge 

 referred to above, point to this stage. As the remnant of the 

 first- year blade is w^orn away as soon as the new blade has start- 

 ed, at least on our coasts, a favorable opportunity must be caught 

 to observe the actual alternation of the blades. Eosenvenge ob- 

 served on the coast of Greenland that the lower part of the old 

 blade of A. grandifolia J. Ag. remained still unworn in summer. 



BörgesenI) has discredited the observation by Wille '^) who 

 writes, "dieses Endblatt fällt jeden Herbst ab und w^ächst von 

 neuem heraus im Lauf des Winters." He confesses that he has 

 " only seen specimens from April to August and from October to 

 December : " and he fills up this gap with observation on the plant 

 by Mr. E. Easmussen, Director of the Faeroese High School. It is 

 very much to be regretted that he had no winter specimens, in- 

 dispensable forms for making a conclusive remark on the problem. 



Granting the view of Böegesex as established from his obser- 

 vations on the Faeroese Islands and strengthened by Easmussen's 

 note, and as true for Alaria plants in the North Atlantic, the dif- 

 ference between his view and that of the others may be condensed 

 to tlie question whetlier the renewal of the blades of Alaria is 

 gradual or sudden. It will be wisest to answer the question 

 thus :— " the renewal of the blades of Alaria may be gradual or 

 sudden according to the conditions of the place where the plant 

 grows." Still it is true that there is more evidence of sudden 

 growth of the blade at a certain time of the year, than of the 

 uniform speed of growth throughout the whole year. 



I will here take this opportunity to relate briefly the Hfe 



1) I3ÖEGESEX : Mar. Algae of the Faeroes, p. 459. 



2) WiixE : Beitr. zur Physiol. Annt. der Laminariaceen, p. 7. 



