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



269 



The branches are placed in the 

 axil of the trichoblast, or more 

 correctly they are pushed a little to 

 the left side of them (Fig. 263). 



By its way of growing and whole 

 construction and habit this plant re- 

 minds one very much of the prece- 

 ding species, but being quite sterile 

 it is impossible to give a more exact 

 definition of it. 



Found once in shallow water near the 

 shore in Store Nordsidebugt (Magens. Bay), 

 St. Thomas. 



3. Polysiphonia variegata (Ag.) Zan. 



Zanardini, G., Synopsis alg. mar. 

 Adriat. in Memorie Real. Accad. d. To- 

 rino, Serie II, T. IV. 1842, p. 162. J. 

 Agardh, Spec. Alg., vol. II, 3, p. 1030; 

 KuTziNG, Spec. Alg., p. 821; Tab. Phycolog., 

 XIII, tab. 81. Harvey, Phycolog. Brit., 

 pi. 155; Nereis Bor. -Am., part II. p. 45. 

 Thuret et Bornet, Etudes Phycolo- 

 giques, p. 86, pi. 42. Falkenberg, Rho- 

 domelaceen, p. 119, tab. 21, fig. 30. Ber- 

 THOLD, Beitr. z. Morphologie und Physio- 

 logie der Meeresalgen (Pringsh. Jahrb. 13, 



Pl. 



Fig. 264. Polysiphonia variegata (Ag.) Zan. 



Basal part of a filament with rhizoids. 



(About 260:1). 



Fig. 263. Polysiphonia spec. 

 Part of filament near its sum- 

 mit with trichoblasts and 

 branches. (About 350 : 1). 



XX. fig. 8—15)- 



Hutchinsia variegata Ag. 

 Systema, p. 153. 



Cfr. De-Toni, Sylloge 

 Alg. Vol. IV. Sect. Ill, p. 

 922, ubi syn. pluria. 



The plant grows upon 

 the roots of the man- 

 groves and forms dense 

 bushes up to 10 cm or 

 more in height. It is 

 fastened to the substra- 

 tum by means of nume- 

 rous rhizoids issuing 

 from the decumbent 

 creeping filaments (Fig. 

 264). The rhizoids are 



