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



71 



only in the summits of the frond is it not so complete allowing 



the red-brown tips of the assimilating filaments to protrude. 



Also the cystocarps project above the calcareous layer and are 



seen in the fruiting specimens as dark red dots (comp. fig. 71). 

 The assimilating filaments have, as pointed out by J. Agardh, 



a corymbiform outhne (Fig. 72). They reach a length of about 



200 /^ or somewhat more. 



They are 4 — 5 times repea- 

 tedly forked. The uppermost 



cells are pearshaped or broad 



oval, about 10 — 12// thick 



(Fig. 73 b) ; lower down in 



the filaments the cells grow 



longer, at length becoming 



subcylindric. The lowermost 



cells are about 16 // thick. 

 The central filaments 



consist of subcylindric cells 



somewhat tapering towards 



the ends (comp. figs. 72 and 



74 a) ; they are about 20 — 40/^ 



thick or more, and often reach 



a length up to 20 times their own diameter. They have very 



thick walls. Between these thicker filaments run thinner ones 



(lat, about 8//), as the 

 transverse section of the 

 medullary tissue shows 

 (Fig. 74): 



These thin filaments 

 originate from the lower- 

 most cells in the assimila- 

 ting filaments (comp. fig. 

 75 a). They run between 

 or creep along the medul- 

 lary filaments ; and from 

 those near the surface 

 erect filaments arise (comp. 



fig. 73 a). They are somewhat branched and consist of oval cells ; 



they grow up between the assimilating filaments. As they have 



well developed chromatophores they may be considered as a kind 

 of secondary assimilating filaments. 



The carpogonial branch is borne upon one of the cells in the 



Fig. 71. Liagora valida Harv. 

 Part of a plant. (About 3:1). 



Fig. 72. Liagora valida Harv. 



Assimilating filaments with carpogonial 



branches. (About 60 : 1). 



