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



353 



Fig. 348. 



Asparagop- 



■sis taxifor- 



mis (Delile) 



Collins et 



they bend upwards becoming erect shoots. The branchlets 

 are vigorously developed, conical in shape with a broad 

 base and a more or less acute summit (cp. Fig. 347). 

 They fix the plant to the substratum through numerous 

 recurved rhizoids breaking out from their summits. 

 These rhizoids are often rather long, cylindrical, with 

 transverse walls, and attach themselves to the substra- 

 tum: stones, shells, calcareous algæ etc. 



The erect shoots reach a height of about 20 cm. They 



are barren in their basal part ; richly pinnately ramified 

 Hervev- • ,i . 



Summit" of m the upper part. 



the thallus. The thallus increases by means of an apical cell 



250 -T) from which segments are cut off by obhque walls in vari- 

 ous directions (Fig. 348). From these segments the cen- 

 tral cells originate and the peri- 

 pheral cells, too, which through 

 numerous divisions are divided 

 into the epidermal parenchyma- 

 tic tissue. 



The branches grow out at an 

 early stage even before the seg- 

 ments are divided. They begin as 

 small roundish outgrowths from 

 the segments, two from each. Of 

 these outgrowths the largest one 

 issues at the broadest side of the 

 oblique segment appearing earlier 

 than the other, smaller one, and 

 this different stage of vigour and size 

 of each pair of branches is kept 

 and clearly seen later on also 

 in the older parts of the plant. 

 Furthermore, besides this different 

 development, the two branches of 

 each pair are not placed exactly 

 opposite to each other, but a little 

 obHquely (cp. Figs. 348, 349a). 

 In the fully developed thallus 



Dansk Botanisk Arkiv, Bd. 3. Nr. X (191 9). 



Fig. 349. Asparagopsis taxiformis 

 (Delile) Collins et Hervey. 



a, part of a branch showing the ra- 

 mification, the lowest branchlets to 

 the right with a young cystocarp. 



b, transverse section of a thin branch- 



let, (a, about 25:1; b, 80:1). 



23 



