THE SEED 



33 



like the leguminous seed, absorb a great amount of water, 

 and not infrequently this amount is equal to the weight of 

 the seed itself, and in some of the clovers it amounts to more 

 than the weight of the seed. 



A second requisite for good germination of a seed is the 

 proper amount of water in the soil. The soil should be wet 

 but not sticky. The seeds must be in intimate contact with 

 the soil at many points and the soil should be fine and com- 

 pactly firmed about the seed so the water in the soil can be 

 used. In addition to the proper amount of water in the soil 

 a warm temperature favors the absorption of water, and 

 hastens the germination. 



Fig. 7. — Longitudinal section of a double seed pot used to regulate the 

 amount of water for very small seeds. 



Regulation of Water. — The calling of a dormant embryo 

 of a seed into life must take place gradually. The chief 

 difficulty lies in the fact that seed require widely varying 

 amounts of water, depending upon the species, the soil, 

 the season of the year, the age, the size, and the state of 

 development. The structure of a seed itself often reveals 

 its requirements as to water. Seed with hard and thick coats 

 require more water than do those with thin soft coverings. 

 Large and heavy seed are less liable to injury by too much 

 water than the small weak ones. Fresh and vigorous seed 

 will endure more moisture than old ones, and to know the 

 requirements of any species, it is usually necessary to know 

 3 



