GERMINATION AND GROWTH 39 
water chinquapin (Nelumbo) have germinated after more 
than a hundred years, and moss spores preserved in her- 
bariums, after fifty. But the records in such cases are not 
always trustworthy, and there is absolutely no foundation 
for the statements sometimes made about the germination 
of wheat grains found preserved with mummies over two 
thousand years old. If kept perfectly dry, however, seed 
may sometimes be preserved for months, or even years. 
Peas have been known to sprout after ten years, red clover 
after twelve, and tobacco after twenty. Ordinarily, however, 
the vitality of seeds diminishes with age, and in making ex- 
periments it is best to select fresh ones. Those used for 
comparison should also, as far as possible, be of the same size 
and weight. 
35. Effect of precocious germination. — It has been found 
by experiment that plants raised from immature seed, when 
they will germinate at all (Exp. 32), yield earlier and larger 
crops than the same kinds from mature seed. Early toma- 
toes and some other vegetables are produced in this way. 
The majority of seeds, however, require a period of rest 
before beginning their life work. Those that are forced to 
take up the burden of “ child labor” show the effect of 
such abnormal condition by yielding fruits that are smaller 
and less firm than those raised from mature seed, so that 
they do not keep well and have to be marketed quickly. 
Under what circumstances does it pay to cultivate such 
fruits? 
Practical Questions 
1. What are the principal external conditions that affect. germination ? 
(Exps. 26-29.) 
2. What effect has cold? want of air? too much water? 
3. Is light necessary to germination? 
4, What is the use of clipping seeds? (Exps. 12, 13, 14, and Material, 
23) 
5. In what cases should it be resorted to? (Exp. 31.) 
6. Why will seed not germinate in hard, sun-baked land without 
