maturity and produce fruit. Between this, its extreme limit, 

 and the level of half-tide, the main crop is developed, the fronds 

 attaining a greater size with the increasing depth of water ; but 

 beyond half-tide we rarely, if ever, meet with Fucus canalicu- 

 latus. It evidently requires by its organization, exposure to the 

 atmosphere for a considerable period each day. Unlike most of 

 its congeners it rarely covers wide spaces of rock, but more com- 

 monly grows in scattered tufts in places where, on the recess of 

 the tide, the water rapidly drains off. It thus shows, in all its 

 habits, a peculiar adaptation for drought, and its tough and close 

 texture admirably fit it for long resisting the drying effects of 

 sun and air. Still, it often becomes quite dry and crisp in a hot 

 summer's day, and yet recovers life and flexibility on the return of 

 the tide. None of our marine plants are less variable in character. 

 Its channelled stem is always recognisable, and its ramification, 

 if the frond be not injured, is invariably dichotomous. In cases of 

 accidental injury, however, the wounded parts become proliferous 

 and throw out numerous branches without order, converting such 

 specimens into dense bushes. 



Fig. 1. Fucus canaliculatus : — of the natural size. 2. Part of a receptacle, with 

 its immersed conceptacles. 3. Section of portion of the same, one of the 

 conceptacles cut through. 4. A spore. 5. Some of the filaments which 

 accompany the spores : — all more or less highly magnified. 



