O70 PLANT s'rnniES 



seeds being represented l)y 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 oven 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 i^lantlet withhi 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 OTie. 



Just how long difli'erent 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 tliut whea.t 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 arc water, heat, and oxygen. Seeds vary in 

 tlie amount of water and heat absolutely needed, hut for 

 terrestrial plants all tlie siiital)lo conditions arc supplied 

 l)y bui-ial in h)ose, moist soil, at tlie temperatures which 

 prevail during the growing season. 



'I'his so-called germiimtion is merely a renewal of the 

 growth of the eml)ryo, whicli 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, fixid iiiatrridi, stored witlun the seeil, most com- 

 monly as starch or oil ; o.r/ffjci/, to lie usetl in respiration ; 

 ivntrr, ii) put tlie cells in proper <'ondition for work, and 

 to act as an agent of transfer; and a sttilablc tcnipcrd- 



