458 SPERMATOPHYTES (SEED PLANTS) 
and spread apart and the seeds fall out. Although the seeds are 
protected between the scales, they are not enclosed as the seeds of 
a Bean or an Apple are. They are on the outside of the structure 
which bears them, — whence the name Gymnosperms. 
The seeds are dispersed by the wind and usually do not germi- 
nate until the next spring after dispersal. In germination the 
axis (hypocotyl) of the sporophyte elongates, forming an arch 
and drawing the cotyledons out of the ground, and at the same 
time the tap-root at the lower end of the hypocotyl becomes 
established in the soil. By the straightening of the hypocotyi 
the green cotyledons are lifted into the air and sunlight, and the 
sporophyte soon becomes independent of the seed. After a 
number of vears of growth, it begins to bear strobili, thus com- 
pleting the life cycle of the Pine as shown in Figure 406. 
In summarizing it should be noted that the Pines have two 
kinds of strobili, reduced gametophytes, pollination, and pollen 
tubes, features which were pointed out as the notable ones of the 
Cycads. But in contrast with the Cycads the Pines have more 
massive sporophytes with leaves bearing no resemblance to those 
of Ferns, and also the Pines have abandoned swimming sperms 
and conduct the sperms to the eggs through pollen tubes. 
In pines the cones mature the second fall after pollination, but 
in some genera of the pine family, as the Spruces illustrate, sexual 
reproduction proceeds more rapidly, although similar in nature, 
and the cones mature the fall following pollination. 
