F. Børgesen : Rhodophyceæ of the Danish W. Indies. 385 



The tetrasporangia are formed in the branchlets. The fertile part 

 of these is thicker than the sterile one. The quite short branchlets 

 become fertile in their whole length, the longer in their upper 

 end; sometimes a fertile zone is found in the middle part of a 

 branch (Fig. 369). 



The plant grows in shallow water near the shore in some- 

 what exposed places where the waves often dash the rocks con- 

 stantly. It seems to me rather probable that this plant is only 

 but a dwarfish form of the preceding species adapted to the 

 conditions of life of the more exposed localities. 



The plant has been found with tetraspores in the months 

 of December and January and with cystocarps in the month of 

 February. 



St. Croix: White Bay; St. Thomas: In several places near Char- 

 lotte Amalia. St. Jan: Cruz Bay. 



Geogr. Distrib.: West Indies. 



Fam. 2. Rhodymeniacece. 



Subfam. 1. Gloiocladieæ. 



Gloiocladia J. Ag. 



1. (xloiocladia spec. 



Only a single sterile plant has been found. It forms a small 

 roundish tuft, about 3 cm high and has, when dry, a beautiful 

 rosy colour. The thallus is flat, repeatedly forked, its divisions 

 being about 3 mAi broad; it seems to be somewhat twisted. The 

 upper ends of the thallus are more or less emarginate with obtuse 

 corners. 



A transverse section of the thallus shows that it is composed 

 of two different cell-tissues (Fig. 370 a, b). 



In the middle of the thallus a layer of very large transparent 

 cells are found; these are about 180 /x thick and often more than 

 400 II long. Seen from above these cells have more or less undu- 

 lated walls and are mostly one and a half to twice as long as broad 

 (Fig. 370 c). For the most part this tissue consists of a single layer 

 of cells, but a few times I have found the large cells divided into 

 a number of smaller cells (compare Fig. 370 a). 



The epidermal layer consists, in the parts nearest to the large 



Dansk Botanisk Arkiv, Bd. 3. Nr. 1 (1920). 25 



