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



121 



All the larger filaments are covered with a cortical layer 

 (comp. Fig. 132) formed by the rhizoids growing out from the 

 base of the branchlets; in the young parts of the branches this 

 cortical layer is not yet developed. 



The tetrasporangia (Fig. 131) of wdiich Derbes et Solier, 

 1. c, pi. 18, flg. 7, give a figure are placed terminally upon the 

 short ramuli. The cells from w^hich the tetrasporangia originate 

 give rise also to some short filaments which are more or less 

 curved round the tetra- 

 sporangia forming in this 

 way a kind of involucre. 

 The tetrasporangia are 

 spherical, tetrahedrally 

 divided; their diameter 

 reaches a length of about 

 75^. The branch which 

 carries the tetrasporan- 

 gia-bearing branchlets 

 are, as pointed out by 

 Zerlang, mostly with- 

 out a cortical layer. 



The antheridial 



stands (Fig. 132) are 

 spherical bodies termin- 

 ally placed upon the 

 ramuli and, in a similar 

 way as the tetraspor- 

 angia, surrounded by 

 curved cells growing out 

 from the cell which carry 



the antheridial stand. This consists of numerous short filaments 

 radiating out from the middle of the stand and at the end of 

 which the spermatia are formed. The diameter of the antheridial 

 stand reaches a length of about 60,«. Duby has 1. c, pi. II, fig. 4 

 given a figure of a branch with antheridial stands. In the 

 branches which carry the ramuli wdth antheridial stands I have 

 mostly found the cortical layer very well developed. 



The cystocarps are spherical and terminally placed upon 

 short branches. Regarding their shape and development upon the 

 whole Bornet et Thuret, Schmitz and especially Zerlang have 

 given detailed descriptions and the first mentioned have further 

 given very fine illustrations, I. c, pi. 48. To these descriptions 



Fig. 132. Wrangelia penicillata C. Ag. Part 



of a male plant with antheridial stand. 



(About 200 : 1). 



