188 PROCEEDINGS OF THE AMERICAN ACADEMY 



a small distance above it. Below the constriction not a cryptostoma 

 is to be seen. The outline in the figure just referred to above was 

 traced from the plant itself while fresh, and is to be compared with 

 Figure 10, in which the permanent oar-shaped base of the adult 

 plant is represented. 



As the blade grows older and the part below the constriction in- 

 creases in size, the constriction gradually disappears. In a specimen 

 of this same collection, 73 cm. long, the last traces of the constriction 

 are to be seen at about 10 cm. above the base of the blade. The base 

 of the blade now becomes more blunt, and begins to take on the shape 

 of the base of the blade of an oar, which is very characteristic of the 

 adult plant. The distinction between stipe and blade becomes for 

 the first time sharply marked. 



This process resembles in almost all respects the process of renewing 

 the blade so well known now in the European species of Laminai'ia* 

 and seen by the writer in most of the species of Laminaria and 

 Agarum of New England. But in this process the old blade, which 

 is thick and is fruiting or has fruited, is cast off, and is succeeded by a 

 new blade of more delicate consistency. In Saccorldza dermatodea, on 

 the contrary, as shown more fully below, the new blade is thicker and 

 denser, and destined to bear the reproductive organs. 



It is about this time in its life-history, also, that the plant grows 

 most actively and reaches its maximum of size. The largest speci- 

 mens I have ever found were growing at Peak's Island, June 28, 1888. 

 The largest specimen of my collection of that date measures 112 cm. 

 when dried. The stipe is 1G.5 cm. long, and the blade reaches a width 

 of 12 cm. Hundreds of plants of this size, and even larger, were 

 growing in that locality at that time. 



Farlow says in his New England Algae, f that the stipe some- 

 times reaches a length of two feet, and the blade a length of six feet. 

 The figures are probably taken from Eastport si:)eciraens, where the 

 species is said to grow more luxuriantly than it does farther south. A 

 specimen in the herbarium of Mr. F. S. Collins of Maiden, Mass., 

 collected at Eastport in August, was in this same stage of growth. 

 The stipe measured GG cm. The blade was short and fragmentary, 

 but measured 21.4 cm. in width. 



In these large specimens the blade is very thin and papery on dry- 

 ing. The color is still a rather yellowish brown, and the cryptostomata 



* Cf. Le Jolis, Examen I., p. 549, 1856; Foslie, Die Lam. Norwegens, p. 23; 

 and earlier writers. 

 t Page 95. 



