234 



water upon stones lying upon the dazzling 

 white sand bottom or in lagoons in muddy 

 water. Often, too, it is found together with 

 other alga? as entangled masses lying loose 

 upon the bottom. From this it is clear that 

 the external conditions under which this 

 plant grows in the West Indies are very 

 variable. 



The specimens found are ramified on all 

 sides (Fig. 222). They have corticated bran- 

 ches and branchlets. Some differences, as 

 to the more or less rich ramification or to 

 the shape and size of the bark-cells, may 

 occur, but it is not here that the essential 

 differences are to be found. It is in the 

 case of the size and shape of the ramuli 

 that we find the chief differences (comp. 

 fig. 223). These may be thick, or thin, 



Fig. 223. Spyridia fila- i n some specimens they have a broad base 

 mentosa (Wulf. ) Harv. , , , ,, ., 



a, a ramulus with long and ta P er evenly upwards, in others they 



cells from the specimen have nearly the same breadth along their 

 figured in Fig. 222. b, a 111 .1 T,, n . j 



ramulus with short cells whole length. The first mentioned end in a 



from the specimen figu- long attenuate spine, the last mentioned in 

 red in Fig. 224. (About i - rp, . ., ,. 



100-1). a snor t spine. Ihe cells in the ramuli are 



either cylindrical, or barrel-shaped, in some 

 specimens nearly as long as broad, in others often more than 

 three times as long as broad. No doubt 

 these variations are due to the influ- 

 ence of different external conditions. 

 For instance specimens growing in 

 more open places, upon coral reefs etc. 

 in strong light have vigorous, but 

 mostly short ramuli with short cells, 

 while specimens from lagoons growing 

 in the shade of the mangroves have 

 long, thin ramuli with long cells. In 

 some specimens I have found numerous 

 long, thin hairs issuing from the cortical 

 cells; these were growing in an open Fi g. 2 2*. Spyridia 

 place with much light. (Wulf.) Harv. Part of speci- 



The figure (Fig. 222) shows a part men with short robust ra- 



& muh from Cruz Bay, St. Jan. 



of a specimen from a more protected (About 16 : l). 



