1916 



Fallisj on Laminariaceae 



143 



15 to 65 meters and expecting them to live much nearer the surface, where 

 there is a difference in pressure, temperature, light and aeration, would 

 surely affect their rate of growth. There was a marked increase in the 

 growth of those plants suspended 4 meters below the surface of the water 

 over those suspended .6 meter below. But the same general principles 

 that appW to the growth in the otlicr Laminnria type of plants apply to 

 Cymathere, Agarum, and Egregia, though the rate of growth is much slow- 

 er. The removal of the thin ])ortion of the blade from the midrib does 

 not affect the growth in length of the rib (Figs. 1,2). But the expanded 

 portion of the blade is not again formed unless some vestige of this is 

 left on the midrib. 



Some sporophylls of Alaria were traced from their beginning as mere 

 knobs to expansions 16.8 cm. long. Their average daily elongation was 

 5.5 mm. Their rate of growth varied from 1 to 15 mm. daily, depending 

 r.pon the size and development of the sporophyll. After attaining con- 



