152 SEA-WEEDS. 



turn], a plant common on our rocky shores, and 

 often attached to corallines. It generally grows 

 in tufts about two inches long, sometimes of bright 

 red, but at others more purplish. It is stiff and 

 rigid, and has a singular structure, Most persons 

 know those common plants of our moist lands, 

 the Equisetums or Horse-tails. The rigid branch- 

 lets of these weeds break off at intervals where 

 they are jointed ; and this sea-weed snaps in pieces 

 just in the same way at the joints ; and a circle of 

 small clear spines surrounds each joint, rendering 

 the plant very beautiful. 



A genus of our marine plants has been named 

 Griffithsia, by Professor Agardh, in honour of 

 Mrs. Griffiths of Torquay, whose investigations on 

 British sea-weeds have contributed very largely 

 to all that is now known respecting them. The 

 coralline-like Griffithsia (Griffithsia corallina}^ is 

 much like a coralline in its form, as the joints in 

 the main stem are swollen, so as to give them a 

 beaded appearance. It is of a bright pink colour, 

 darker at the joints, and it stains the paper red on 

 which it is placed. This plant is common on the 

 southern shores of England, but becomes more 

 rare as we advance northward. It is not so 

 general as the bristly species (Griffithsia setacea), 

 which is a rigid hard sea- weed of a rich crimson, 

 changing to a dull orange colour. If placed in 

 fresh water, this plant loses all its firmness, be- 

 comes flaccid, and turns to a bright orange. This, 

 however, is not the only change which it under- 

 goes. When placed in fresh water for a few 

 seconds, and then taken from it, it gives out a 

 crackling or crepitating noise, which Dr. Drum- 

 mond, who first discovered this peculiarity, de- 



