SEEDS AND SEEDLINGS 



the growth of the ovary and seed. These two sex cells will 

 become the embryo plant of the seed. If an egg cell remains 

 unfertilized, the ovule will remain about as large as the head 

 of a pin while the ovary will soon die and wither if none of 

 its ovules are fertilized. 



The embryo of the seed is the resting or dormant stage 

 of the small living plant within the seed. It consists of (1) 

 a radicle pointing toward the micropyle, which emerges first 

 in germination and develops into the root system of the 

 plant; (2) one or more cotyledons; and (3) the plumule 

 which is a group of folded leaves so small that it is seen with 



Fig. 3. Iris. A, B, surface view and cross section of the fruit. C, lengthwise 

 section of a seed. (After Smith et al., A Textbook of General Botany. By permission 

 of The Macrtiillan Company, publishers.) 



difficulty between the cotyledons just above (4) the epi- 

 cotyl. The plumule produces the shoot when the seed germi- 

 nates (Figs. 1 and 2, D). It will be noted that in many 

 seedlings the first leaves above the cotyledons differ in size 

 and shape from those appearing later. Many legumes have 

 simple leaves above the cotyledons and all later ones are 

 compound. 



The largest part of the seed is that which contains the 

 supply of stored food for the growth of the seedling until it is 

 large enough to make food. In albuminous seeds, such as 



