16 THE MARINE BOTANIST. 



toug-li, witli a midrib j the air-vessels are round^ 

 large, and mostly in pairs. When in fruit, the 

 tips of the fronds swell up and are filled with 

 mucus ^ those containing* spores are of a greenish- 

 olive colour, while the receptacles with antheridea 

 are of a more or less orange-yellow hue. A curious 

 bladderless variety of this plant j3 Balticus, is found 

 in salt marshes and places only occasionally flooded 

 by the tide. The fronds are narrow, and not more 

 than two inches high, crowded together, and of a 

 yellowish colour. Fucus vesiculosus is much used 

 in the manufacture of kelp, and furnishes excellent 

 winter provender for the cattle in the western 

 islands of Scotland. 



FUCUS CERANOIDES.— WAXY FUCUS. 



A small and far more delicate species than the 

 preceding, without air-vessels ; the receptacles are 

 borne by the side branches, not very large, forked 

 and pointed at the ends. Colour a greenish or 

 brownish olive : the substance is much thinner 



