80 SEAWEEDS 
size. In the last-mentioned genus the stalk is long, 
slender and solid at the base, but becoming hollow 
and broader above; near the top it expands into a 
globular or elongate pear-shaped bladder, bearing 
Fic. 16.—Macrocystis pyrifera. a, diagrammatic sketch of habit, the sporo- 
phyllous leaves at base of stem. b, apex of frond showing leaves splitting off. 
Reduced. 
two bunches of leaves. In Macrocystis, the most 
gigantic of all the forms, attainimg frequently a 
length greater than that of any other plants and 
measuring hundreds of feet, the leaves are formed on 
one side only of a scimitar-shaped blade by parallel 
