61 



etc., food products produced during the vegetative phase of the mother plant 

 and now stored in proximity to the embryo for its use in the early stages 

 of germination and growth. The amount and nature of the food present in 

 the endosperm is dependent on a number of factors, such as the vigor of 

 the mother plant, the water and soil nutrients available, temperature, etc. 

 The amount of organic material produced by the mother plant and drawn 

 from her by the developing embryo and endosperm is too well known by the 

 farmer to need further discussion. The weight of his cereal crop is essen- 

 tially the weight of the food supplied by her, or rather drawn from her. 

 The relation of the developing embryo and endosperm to the mother plant 

 is not without interest. The relation is one of host and parasite and results 

 in a great weakening, or even the death of the plant through exhaustion. 

 The latter is well illustrated by the century plant. Its vegetative phase 

 extends over a period of ten to fifteen years. During this period the plant 

 elaborates from the inorganic materials offered by its environment, the 

 organic food materials which it stores in its fleshy leaves. These leaves in 

 vigorous specimens may be six feet in length, nearly a foot in width, and 

 four inches in thickness. They represent the stored materials of the whole 

 vegetative period of the plant. When the reproductive period sets in, the 

 bud in the center of the rosette grows into an enormous flower stalk four 

 or more inches in diameter, twenty feet or more in height, and branching 

 at the top. Hundreds of flowers develop, and seeds with organic material 

 stored, mature. In marked contrast stand these two phases. In a few 

 weeks the organic material slowly accumulated during ten or more years 

 of vegetative life is rapidly consumed in the development of the flower stalk 

 or completely withdrawn by the parasitic nature of the developing seeds. 



FIG. III. Germination of corn harvested in the milk stage 

 and dried before testing. 



