126 



Dansk Botanisk Arkiv, Bd. 3. Nr. 1. 



This species is a marked littoral alga. It grows together 

 with Ulva etc. near the surface of the sea in places where the 

 waves constantly dash the rocks. The thallus is tough and 

 elastic with a glabrous and lubricous surface, very apt to grow 

 in such localities. 



The specimens collected (comp. Fig. 134) reach a length of 

 up to 40 cm and more. They are fastened to the substratum by 

 means of a small disc. Immediately above this the thallus is 



terete but it soon be- 

 comes compressed and 

 passes evenly into 

 the ribbon -like or leaf - 

 like frond. This differs 

 very much in shape, 

 sometimes it is more 

 narrow, sometimes broa- 

 der i) ; some specimens 

 are not divided at all 

 but this is rare; most 

 of the specimens are 

 more or less lacerated 

 or what is more 

 common bear numerous 

 smaller and larger pro- 

 liferations along the 

 margin. Towards the 

 summit the thallus itself 

 and the proliferations 

 are evenly narrowed and 

 run out often into long 

 thin prolongations. The 

 margin of the whole frond is more or less undulated. The colour 

 is a deep red-violet. 



Kützing's above quoted figure seems to me to give a fairly 

 good illustration of the plant. 



A transverse section (Fig. 135) of the thallus shows that a 

 marked difference between the medullary tissue and the cortical 

 layer is present. 



The medullary tissue consists of more or less cylindrical much 



.Fig. 134. Grateloupia cuneifolia J. Ag. A 

 smaller much divided plant. (About half 

 natural size). 



1) The broadest specimens in my collection are 4 — 5 cm broad. 



