1912] Goodspeed : Nicotiana Hybrids 109 



9. From the hea\'y seed 39 per cent of "dominants" (re- 

 sembling macrophylla) , 9 per cent of "recessives" (resembling 

 virginica) and 52 per cent of "intermediates" and "blends" 

 could be distinguished. 



10. From the medium-weight seed 26 per cent of "domin- 

 ants, ' ' 25 per cent of ' ' recessives ' ' and 49 per cent of ' ' blends ' ' 

 and "intermediates" can be reported. 



11. From the light seed 18 per cent of "dominants," 33 per 

 cent of "recessives" and 49 per cent of "blends" and "inter- 

 mediates" could be recognized. 



12. The seed produced by close fertilizing one plant of N. 

 Tabacum var. macrophylla, which was harvested in 1907, showed 

 under a reading-lens a much greater degree of uniformity in 

 shape and size than did the F^ hybrid seed similarly examined. 

 The same was true for the seed of N. Tabacum var. virginica 

 similarly produced on two successive years — 1906 and 1907. 



13. The average weight of 100 virginica seeds of 1906 was 

 0.0001 grams less than the average weight of 100 virginica seeds 

 of 1907. 



14. The average weight of 100 virginica seeds of 1906 or 

 1907 was 0.009 grams less than the average weight of 100 macro- 

 phylla seeds of 1907. 



IX. DISCUSSION OF RESULTS 



The results obtained when the rate of germination of seeds 

 of different weights, under the germinating conditions described 

 above, was compared, are interesting and of some significance. 

 As has been mentioned above, the differing degrees of permeabil- 

 ity to water and oxygen probably explains the early germination 

 of most of the light seed that did germinate at all and the slow 

 germination of the heavy seed. The seed of 1906 and 1907 of 

 N. Tabacum var. virginica and of 1907 N. Tabacum var. macro- 

 phylla has, within the past month, been germinated in an 

 unheated propagating house. One hundred seeds of each year 

 and of each variety were used. The macrophylla seed showed 

 the first signs of germination within nine days and at the end 

 of sixteen days 89 per cent had germinated. The germination of 



