44 BRITISH SEA-WEEDS. 



Fucus Mackaii. Mackay's Wrack. 



Frond cylindrical, or slightly flattened, slender, much 

 divided into forked branches. Air-vessels, when present, 

 below the forkings of the frond, about half an inch long 

 and one-fifth of an inch in diameter. Fructification in pen- 

 dulous, lance-shaped receptacles on slender stalks, spring- 

 ing from the sides of the lower part of the branches. 



The recorded Britisb habitats of this rare plant are 

 all in Ireland and Scotland. It was first found on the 

 coast of Connemara, by Mr. Mackay, and is named 

 after him. It has been considered to be only a variety 

 of F. nodosus ; but more careful examination has not 

 confirmed this view, and it is now recognized as an esta- 

 blished species. It grows in a round tuft, about a foot 

 in diameter, somewhat like mistletoe, without a root, 

 and not attached to anything, but resting on the sand 

 or mud, or among rocks. 



Fucus canaliculatus. Channelled "Wrack. 



Frond narrow, channelled on one side, rounded on the 

 other, without either midrib or air-vessels, forked. Fructi- 

 fication in tubercular, forked receptacles, at the tips of the 

 branches. 



With the exception of the newly-discovered F. anceps, 

 this is the smallest of our native Fuci, being rarely more 

 than eight or nine inches high, and often only two or 

 three. It grows very near high-water mark, and occa- 

 sionally in situations where the spray alone reaches it, 

 but in these positions it is very stunted. 



Fucus anceps. Two-edged Wrack. 



Frond repeatedly forked, flat in the lower part, tapering 

 above, with an indistinct midrib. Air-vessels, none. Fruc- 



