38 
THE PLANT WORLD. 
water. The pollen grains are very few, only about ioo to each 
anther, but a large output is secured by the production of a large 
number of staminate flowers on each axis. The pollen grains are 
smooth, very large, 175 ft, contain oil and starch and are heavier 
than sea water. 
At low tide pistillate buds are above water and at anthesis the 
hairy spathe leaves open and the whole inflorescence rests with 
its axis in a horizontal position upon the water. The perianth of 
the pistillate flower consists of three short sepals and three long 
reddish petals, the latter being much folded both longitudinally 
and transversely as a result of much growth while being confined 
by the sepals. These folded petals extend beyond the spathe 
leaves after they have opened. The stigmas are sessile upon the 
six-lobed ovary. The six parietal placentae split early, forming 
large air cavities which aid in floating the flower until the growth 
of the embryos fills the cavities and increases the density of the 
whole organism, causing it to sink to the bottom after the ovary 
has been shed. 
Being a marine plant and subjected to tidal changes, the prob¬ 
lem of pollination with Enalus is much more complex than with 
many other hydrophilous plants. As stated above at the time of 
pollination the pistillate inflorescence is floating with its axis in 
a horizontal position with the extended petals resting upon the 
surface of the water without becoming wet. As the staminate 
flowers float about on the water in large numbers some of them 
are caught by the curious folds in the petals of the pistillate 
flowers and held fast in spite of wind and currents. With the 
rising of the tide the pistillate inflorescence is submerged and its 
axis takes a vertical position. The heavy pollen then drops upon 
the stigmas. From the above it will be seen that the first step of 
pollination is effected only during low tide while the second takes 
place during high tide. Before separating from the plant under 
water the perianth of the staminate flower forms a balloon-like 
body enclosing a bubble of gas. The density of this gas, of 
course, depends upon the depth of the water. It is evident, there¬ 
fore, that during low tide the specific gravity of the whole flower 
is less, causing the pedicels to rupture at that time. “ Thus there 
