RHODYMENIACEAZ. 



PART II. 



becomes horny when dried. It is reproduced by te- 

 traspores, in large oval groups scattered all over the 

 surface, often prominent on one side only, and, in some 

 rare instances, spores in prominent oval conceptacles 

 are immersed in the lesser frond divisions. Besides 

 these are warts composed of radiating threads, possibly 

 antheridia, but not made out. 



The Ehodymeniacese are sometimes filiform, but for 

 the most part they are compressed flat cellular fronds, 

 spreading widely from a short delicate stem. They are 



Pig. 26. A, Rhabdonia Conlteri, portion of nucleus. B, Sphaerococcus coronopif olius ; 

 portion of nucleus and single spore, c, Wrangelia penicillata, spore threads. D, Cruoria 

 pellita, tetraspores. 



usually of a blood red, but Bhodymenia palmata, or com- 

 mon Scotch dulse, is of a dark purple. The tetraspores 

 are variously disposed, and simple or compound globu- 

 lar conceptacles containing nuclei are either attached 

 externally to the filiform fronds, or partly immersed 

 in those that are foliaceous. The spores are produced 

 in the joints of moniliform threads within the nuclei, 

 which are sometimes divided into two chambers by 



