io6 GERMINATION OF THE MICROSPORE 



also often begins while in its sporangium but in other cases 

 growth begins after it has escaped from the sporangium and has 

 been carried by the wind or some insect visiting the flower for 



FIG. 78. The germination of the megaspore complete. The plant thus 

 formed consists of a female gamete or egg cell, $, below which are two 

 synergidae and in the center are the two uniting polar nuclei, p, while at 

 the opposite end of the sac are three antipodal cells, a; mi, micropyle ; 

 i, integuments ; f, stalk or funiculus in which a vascular bundle, v, has 

 been developed to transport foods from the ovary to the ovule. 



food, to the stigma of the pistil. The stigma is admirably 

 adapted to hold the microspore, being provided with minute out- 

 growths, and frequently sugary solutions are exuded which 

 fasten the spores to the stigma. The real importance of these 

 sugary solutions is to nourish the microspores. It is evident 

 that these minute dust-like cells can not contain sufficient food 

 to bring about any considerable growth. It is noteworthy that 



