14 CRYPTOGAMIA ALG^. 



Upon rocky fhores, at low-water mark, frequent 

 VII. 



This fpecies varies almoft without end. 



The moft general appearances of it anfwer how- 

 ever to the following defcription. 



Many radical leaves arife from the fame root or 

 bafe, and fpread upon the rocks in a circular 

 form, or (as the water often leaves them) in 

 the form of an arc of a circle. Each leaf is 

 moft commonly about four inches long, and 

 one-eighth of an inch wide, but varies from 

 one to feven inches in length, and from one- 

 twelfth to an inch in breadth ; of a tough, 

 cartilaginous fubftance, horny when dry, pel- 

 lucid when held between' the eye and the light; 

 often of a bright purple color, fometimes of 

 *a green color, moft ufually a purple inter- 

 mixed with green, and frequently, when caft 

 upon the ftiores, and expos'd to the fun and 

 air, of a yellowifti-white or horn-color. 



Again, each leaf is plane or flat on both furfaces, 

 intire on the edges, of an uniform texture, 

 without rib, fimple, undivided, and narrowed at 

 the bafe, wider and dichotomous upwards, but 

 divided into fo many fegments towards the 

 extremity, that, taken colledlively, they re- 

 femble a Corymhus. Each fegment is bifid at 



the 



