A well known plant, the common Sea-girdles or Tangle, which 

 grows to a large size on all rocky coasts. Our figure may 

 appear a caricature to persons acquainted only with the 

 plant in the state in which it is usually cast ashore, but I have 

 purposely selected a specimen to illustrate its very curious 

 mode of growth. The root and stem are perennial, but the 

 many-cleft leaf is renewed every season and the old one cast off. 

 Our specimen represents the nearly perfectly formed leaf of the 

 present season and the base of the leaf of last year adhering to 

 the tips of its segments. The mode of growth is as follows : 

 As soon as the existing frond has served its purpose and begins 

 to grow brown, an expansion commences between its base and 

 the apex of the stem. This expansion continues to increase in 

 length and breadth till it has attained a considerable size. We 

 have then a large ovate lobe at the apex of the stem, separated 

 by a deep constriction from the old frond. As yet this lobe is 

 quite entire ; but after a while longitudinal splits, commencing 

 near its margin, and continuing towards its centre begin to 

 appear. These widen and lengthen by degrees, and at last the 

 outer ones reach the decaying base of the old frond ; a rupture 

 ensues, and the tip of the new segment is free. This process is 

 continued, until, when many segments have thus been formed, 

 the connection between the old leaf and the now nearly perfect 

 new one is so much weakened, that the former adheres by a very 

 small surface, and is soon cast off altogether. Our figure is taken 

 from a specimen in which this is about to take place. 



This mode of growth appears common to all the Laminariae, 

 in many of which Mrs. Griffiths has been the first to observe it ; 

 and I take this opportunity of expressing my warmest thanks to 

 that lady for a magnificent suite of the present species, exhibiting 

 the growing frond in all stages of its developement. 



Fig. 1. Plant of Laminaria digitata, (small), just before casting the frond of 

 the previous season. 2. Young seedling plant : — both of the natural size. 

 3. Section of the frond, with spores and air cells in situ. 4. Spores : — both 

 magnified. 



