F. Børgesen: Phæophyceæ of the Danish W. Indies. 



17 



6. Ectocarpus breviarticulatus J. Ag. 



J. Agardh, Nya alger från Mexico (Öfversigt af K. Vetensk.-Akad. 

 Forhandl. 15. Jan., 1847, p. 7). 



Ectocarpus hamatus Cr. in Maze et Schramm, Essai de classification 

 des Algues de la Guadeloupe, 2e Edit. 1870-1877, p. 111. 



Vickers, A., Phycologia Barbadensis, part II, pi. 29. 



By means of original specimens collected by Liebmann near 

 St. Augustin in Mexico and determined by J. Agardh I have 

 been able to see that Ectocarpus hamatus of Crouan, so well 

 figured in the "Phycologia" of M lle Vickers belongs to this species. 

 As the description of J. Agardh is rather deficient and M lle Vickers 

 in her "Liste" does 

 not give any descrip- 

 tion of it I here men- 

 tion it in a little more 

 detail. 



The plant forms 



rather large tufts, 2 — 



4 cm high or even 



more, and these tufts 



are again composed 



of thinner and thicker 



rope-like spongy mas- 



T-v n ,, Fig. 10. Ectocarpus breviarticulatus J. Ag. 



ses. By means ol the ° t. -xt, i i i • 



J a, a branch with young plunlocular sporangia. 



numerous hooks and b, cells with chromatophores and a ripe pluri- 



short bent ramuli, locular sporangium, c a hookformed ramulus. 



. ' d, a branch with rhizoid-hke apex. 



spread along the main ( a , c and d, about 90 : 1 ; b, about 190 : 1). 



filaments the whole 



becomes twisted together just as in Ectocarpus tomentosus. The 



growth takes place at any point in the filaments. These are 



about 27 fi thick. The length of the cells is usually 1 — 2 times 



their own diameter, rarely a little shorter or longer. 



The plurilocular sporangia are nearly spherical in shape or 

 somewhat ovoid (Fig. 10 b). They are placed nearly at right 

 angles upon the filaments and have a very short stalk consisting 

 only of a single small cell. The length of the sporangia is about 

 62 [i ; the breadth about 57 ft. 



Unilocular sporangia were not found. 



Instead of hooks the ramuli sometimes run out into thin 

 rhizoids (Fig. 10 d). 



Several small roundish or more irregular discoid chromato- 

 phores are present in each cell (Fig. 10 b). 



Dansk Botanisk Arkiv, Bd. 2. Kr. 2. 2 



