PLANT STUDIES 
seeds being represented by the " core." In other cases, the 
end of the stem bearing the ovaries (receptacle) becomes 
enlarged and pulpy, as in the strawberry. This effect 
sometimes involves even more than the parts of a single 
flower, a whole flower-cluster, with its axis and bracts, be- 
coming an enlarged pulpy mass, as in the pineapple. 
The term " fruit," therefore, is a very indefinite one, so 
far as the structures it includes are concerned. 
247. The germination of the seed. It is wrong to apply 
the term " germination " to the renewal of activity by the 
young plantlet within the seed, as has been shown before 
(page 354), but in the absence of a better word it will be 
used. This " awakening of the seed " is a phenomenon so 
easily observed that it can hardly escape the attention of 
any one. 
Just how long different seeds may retain their vitality 
that is, live in a state of suspended animation is not very 
definitely known. Some seeds have germinated after hav- 
ing remained in a dried-up condition for many years, but 
such stories as that wheat taken from the wrappings of 
Egyptian mummies has been made to germinate are myths. 
If the structures of the seed are normal, its germination 
will follow its exposure to certain conditions, prominent 
among which are water, heat, and oxygen. Seeds vary in 
the amount of water and heat absolutely needed, but for 
terrestrial plants all the suitable conditions are supplied 
by burial in loose, moist soil, at the temperatures which 
prevail during the growing season. 
This so-called germination is merely a renewal of the 
growth of the embryo, which results in freeing it from the 
seed coats, and in enabling it to establish itself for inde- 
pendent living. All the conditions for growth are present, 
namely, food material, stored within the seed, most com- 
monly as starch or oil ; oxygen, to be used in respiration ; 
water, to put the cells in proper condition for work, and 
to act as an agent of transfer; and a suitable tempera- 
