52 BRITISH SEA-WEEDS. 



mid-rib. Fructification imbedded in tbe frond in spots. — 

 LAMrtfAEiA, from the Latin lamina, a thin plate. 



There are several species of this genus, which are 

 widely distributed both in hot and cold climates. They 

 grow generally at and beyond low-water mark, extend- 

 ing into depths of many fathoms. "With one or two ex- 

 ceptions, all the species are of large size, and some of 

 them attain a height of twenty feet. They grow very 

 rapidly, and renew the leafy part of their fronds every 

 year. The new leaf is formed between the top of the 

 stalk and the base of the old leaf, which gradually de- 

 cays and gives place to its successor. This process is 

 very well exhibited in small specimens of L. diyitata, 

 and the young collector should obtain a few plants, show- 

 ing the two fronds in various stages of growth. 



Laminaria digitata. Fingered Laminaria, or 

 Tangle. 



Stem solid, cylindrical, tapering upwards, of varying 

 length ; frond leathery, roundish-oblong, when quite young, 

 entire, rapidly becoming deeply cleft into several strips. 



Small specimens of this species may be gathered in 

 the deeper tide-pools near low-water mark. The larger 

 are cast on shore after storms. It is impossible to pre- 

 serve the latter, but they should always be examined, as 

 many rare small Algse, which delight in deep water, 

 grow on their stems, aud can only be collected in this 

 manner. 



Iiamiuaria digitata, var. stenophylla. 



This plant is figured by Professor Harvey in the 'Phy- 

 cologia Britannica,' and he expresses a doubt as to 



