FUNDAMENTAL PRINCIPLES l8l 
to apply to the resulting diploid organism through all 
stages of its development to maturity. 
165. Two Kinds of Generations. A study of the life 
history of the fern disclosed two distinct phases or genera- 
tions, one bearing spores, and therefore called the sporo- 
phyte (spore-bearing plant) , the other bearing gametes and 
for that reason called the gametophyte (gamete-bearing 
plant). The gametophyte of the fern was seen to be 
entirely independent of the sporophyte, capable of manu- 
facturing its own food by means of its own chlorophyll, 
not dependent upon any other plant, and in some groups 
being perennial, living on from year to year, and giving 
rise to sporophytes that live for only one season. The 
sporophyte, on the other hand, is at first, entirely de- 
pendent upon the gametophyte for its nutrition, living as 
a parasite upon the prothallus, from which it absorbs its 
nourishment by means of the special organ, the foot. 
Gradually, however, the sporophyte puts forth roots, 
capable of taking in water and dissolved mineral sub- 
stances from the soil, and chlorophyll-bearing organs (the 
fronds or leaves), capable of manufacturing organic food. 
As the sporophyte becomes independent, the gameto- 
phyte (with few exceptions, as noted above), perishes. 
A comparison of the two generations shows that the 
sporophyte is the much more complex of the two, being 
clearly differentiated into roots, and leafy shoot. The 
difference in the origin of these two generations results in 
a very fundamental difference in the nature of all the 
cells in each. Since the sporophyte is derived from an 
oosperm (zygote), formed by the fusion of the two 
gametes, all of its cells are diploid, containing material 
derived from both its male and female parentage. The 
