250 



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



Fig. 240. Laurencia 

 obtusa (Huds.) La- 

 mour. var. gelatinosa 

 (Desf.) J.Ag. Trans- 

 verse section of the 

 thailus. (About 60:1). 



in shape. The main stem bears on all sides 

 short branches, usually verticillate. The bran- 

 ches ramify again once or several times, the 

 ramuli in the tetrasporic plants being subcla- 

 vate or nearly cylindrical (Fig. 239). In the 

 male plant, on the other hand, the ramuli are 

 very swollen at their summit (Fig. 238). Female 

 plants were not found. The antheridial stands 

 agree entirely with the description and figures 

 of Falkenberg, Rhodomelaceen, p. 247, pi. 

 23, figs. 13—15. 



Falkenberg states 

 that he found at Naples 

 two forms of Laurencia 

 obtusa growing together in 

 the same locality. These 

 two forms, in all other 

 points identical, differ from 

 each other by their colour : 

 the one is green, the other 

 yellowish red. Collins 

 found the same in Bermu- 

 da. This is also seen on 

 the shores of the islands. 



This variety i s met with 

 even in very exposed pla- 

 ces, for instance it is com- 

 mon along the rocky shore 

 of the north-west end of 

 St. Croix. It grows here 

 often somewhat above the 

 level of the sea and is con- 

 stantly washed by the 

 strong surf nearly always 

 prevailing here. 



Laurencia obtusa is rather 

 common along the shores of 

 the islands. Var. gelatinosa has 

 been found at St. Croix: 

 Northside, Coakley Bay, White 



Fig. 241. Laurencia implicata J. Ag. Part 

 of the thallus. (About 3:1). 



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