RED ALGSE. 189 



direction, the longest near the bottom. These 

 b-anches are often branched in the same manner, 

 and sometimes the branchlets also. All the parts are 

 beset, sometimes thickly, sometimes sparingly, with 

 short, horizontal spines one-tenth to one-third of an 

 inch long. 



The distinguishing mark of the plant is this : The 

 almost or quite naked extremity of the principal 

 branches is turned back at the ends so as to form 

 a hook, often not unlike a fish-hook in appearance. 

 This must not be mistaken for the twining tendrils 

 borne on the end branches of one variety of Cysto- 

 clonium purpurascens. The color is a dark, dull 

 red, with a purplish tinge, which rapidly fades to 

 dirty green and white, when exposed to sunshine or 

 the action of fresh water. It adheres to paper, but 

 not very strongly. 



Order.— RHODYMENIE* £. 

 G&nu%.—RHODYMENIA* Grev. 



Rhodymenia palmata, Grev. 



The palmate or hand-shaped Rhodymenia is so 

 common and SO universally known under the common 



• Rhodymenia = A red membrane. 



