REST PERIOD STUDIES WITH SEEDS 47 



Conclusions. These results are almost identical with those secured 

 the previous year as regards the number of species that have a rest 

 period, viz., a little more than 76 per cent. 



The species of a single order are much alike as regards whether 

 they have a rest period. Also in addition to exhibiting similar require- 

 ments for growth, they are apt to show about the same percentage 

 of germination. 



EXPERIMENT 3 



The seeds of fifteen species of woody plants, repre- 

 senting eleven orders, were gathered before maturity, that is, in the 

 "dough" stage. Half of each was planted at once and the other half 

 air-dried before planting. A set of freshly gathered, mature seeds 

 was planted immediately after harvesting in order to check the results. 



Results from Experiment 3. Only two species (13.3 per cent) of 

 the freshly gathered, green seeds grew, while none of the immature 

 dried seeds germinated. Forty per cent of the ripe seeds sprouted. 



Conclusions. While the number of seeds in the experiment was 

 small, it would appear for the most part, that immature seeds, par- 

 ticularly of woody plants, are unable to germinate. However, if 

 they do grow, germination takes place much more quickly than in 

 mature seeds. Finally, immature seeds of woody plants are easily 

 killed if allowed to become air-dry. 



EXPERIMENT 4 



In the fall of 1912, thirty-one species of woody plants, 

 representing fifteen orders, were tested to find what species 

 have a rest period, value of treatments for breaking the rest that is, 

 for producing quick germination and also the effects of the treat- 

 ments on total percentage of germination. The treatments consisted 

 of drying, soaking in water, etherizing, stratifying, and combinations of 

 these treatments. The seeds that were stratified were frozen in 

 stratification. 



Results from Experiment 4. Of the species planted at maturity, 

 6.5 per cent germinated within two weeks, 58 per cent grew after two 

 weeks while 35.4 per cent did not grow at all. 



The quickest germination resulted from freezing the seeds in 

 stratification, then treating them with ether for twenty-four hours. 

 These grew, on the average, in 22.6 days, while dry untreated seeds 

 required, on the average 50.1 days. This treatment also gave the most 

 complete germination, 43.8 per cent, as compared with 14.5 per cent 

 for dry untreated seeds. 



