352 
PLANT STUDIES 
are dry and powdery, and are scattered far and wide by the 
wind. In the pines and their allies the pollen-grains are 
winged (Fig. 309, />), so that they are well organized for 
wind distribution. This transfer of pollen is called pol- 
lination, and those plants that use the wind as an agent of 
transfer are said to be anemophilous, or " wind-loving." 
The pollen must reach the ovule, and to insure this it 
must fall like rain. To aid in catching the falling pollen 
the scale-like carpels of the cone 
spread apart, the pollen - grains 
slide down their sloping surfaces 
and collect in a little drift at the 
bottom of each carpel, where the 
ovules are found (Fig. 310, A, B). 
The flaring lips of the micropyle 
roll inward and outward as they 
are dry or moist, and by this mo- 
tion some of the pollen-grains are 
caught and pressed down upon the 
apex of the nucellus. 
In this position the pollen-tube 
develops, crowds its way among 
the cells of the nucellus, reaches 
the wall of the embryo-sac, and 
penetrating that, reaches the necks 
of the archegonia. 
232. The embryo. By the act of 
fertilization, an oospore is formed 
within the archegonium. As it is on the surface of its food 
supply (the endosperm), it first develops a long cylindrical 
process (suspensor), which penetrates the endosperm and 
develops the embryo at its tip. In this way the embryo lies 
imbedded in the midst of its food supply (Fig. 313). 
233. The seed. While the embryo is developing, some 
important changes are taking place in the ovule outside of 
the endosperm. The most noteworthy is the change which 
Jia 
FIG. 313. Embryos of pine : A, 
very young embryos (ka) at the 
tips of long and contorted sus- 
pensors () ; J5, older embryo, 
showing attachment to suspen- 
sor (s), the extensive root sheath 
(wh), root tip (ws), stem tip 
(#), and cotyledons (c). After 
STRASBURGER. 
