474 



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



the same branchlet) are found scattered along the branchlet 

 often one from each segment with the exception of the lower- 

 most. A great number of seg- 

 ments, 10 — 12 or more, are 

 present in the fructiferous part 

 of this plant, the central cells of 

 which are easily observable (Fig, 

 430 b); in H. secunda, as men- 

 tioned above, only four to five 

 are present. 



As to the ramification of 

 the main stem 1 have gene- 

 rally found a single bare seg- 

 ment between those with branch- 

 lets and branches, as shown in 

 the diagram (Fig. 429). But 

 modification is often present, 

 compare e. g. Fig. 430 a where 

 two bare segments are found 

 in one case. 



In this form in the main 



stem, nine pericentral cells were 



/ present, in the erect branchlets 



seven only. The diameter of the 



branchlets was about 50 fi. 



In a collection af various 

 algæ from shallow water gath- 

 ered at the shore of Water Is- 

 land at St. Thomas, plants with 

 cystocarps were found. How far 

 these plants really belong to H. 

 tenella I dare not say with cer- 

 tainty. The ramification, at any 

 rate, was the common one an- 

 swering to the diagram of it given 

 by Falkenberg, 1. c. p. 303. 

 As described by Falkenberg, 1. c, p. 309, pi. 3, fig. 10 the 

 procarps are formed in the trichoblasts in the upper end of the 

 branchlets. The branchlets, which bear the cystocarps, become 



I 



Fig. 431. Herposiphonia spec, a and 

 b, plants with cystocarps (compare 

 the text), c, part of tetrasporic plant, 

 (a and b, about 22:1; c, about 50:1.) 



