57 



surface of the frond appears commonly to be smoother than in f. 

 typica, and in all less furnished with local, scaly thickenings than 

 the other forms. However, this apparently often depends on the 

 locality where the plant grows, and I met with specimens which 

 in this respect fully coincide with f. typica. Also in other species 

 I have seen specimens sometimes quite smooth and rather shining 

 sometimes furnished with numerous scaly thickenings. These thicke- 

 nings appear in all to be more common in specimens growing in 

 shallow water with somewhat clayish bottom, or in places with 

 rather rapid tides, and wanting or more seldom to be found in 

 specimens growing in deeper water with harder bottom. 



With reference to the structure the present plant accords in 

 the main with L. fruticulosum and other nearly allied species. 

 The cup-shaped layers of tissue are, in a longitudinal section of 

 a branch, more or less regular and rather distinct, and the inner 

 cells are about 8 — 10 //• long and 5 — 7 fi thick. Thus they are 

 somewhat shorter in proportion to the thickness than those of the 

 named species, often being nearly squarish. In f. patula they are 

 frequently a little coarser than in f. typica, but, so far as I have 

 seen, not exceeding 10 fi in length and 7 fi in thickness, and any 

 limit is in this respect impossible to draw, the cells being as a 

 rule rather varying even in one and the same specimen. 



The very greatest number of specimens that I have seen have 

 been sterile, only some few ones provided with conceptacles of 

 sporangia or cystocarps. The first named organs are scattered 

 over the whole frond or somewhat crowded below the tip of the 

 branches, convex but slightly prominent, more os less distinctly 

 marked, seen from the surface about 200 — 250 jj. in diameter. In 

 this respect f. patula somewhat differs from the other forms, as 

 the conceptacles frequently appear to be a little larger, or up to 

 300 p-, which, howewer, now and then also is the case in the 

 other forms. The roof is intersected whit about 30 — 40 muciferous 

 canals, which are rather crowded in the central portion, and espe- 

 cially in the form patula it appears apt to fall away. I have seen 

 but some few sporangia. The are four-parted, 90 — 110 fi long 

 and 35 — 50 f. broad. 



