1915] Goodspeecl: Germination of Tobacco Seed 241 



istic day and it is peculiar to both older and younger seed. Thus for 

 Nicotiana angustifolia (110/05) the seed aged two, three, five, six, 

 seven, and eight years gave the greatest amount of germination on the 

 seventh, while the four-year-old seed gave the greatest amount on the 

 eleventh daj^ of the germination tests. Likewise, in the case of N. 

 Tahaciim "Maryland", the eleventh day showed the greatest amount 

 of germination for the seed of four different years, while the youngest 

 seed germinated most heavily on the ninth day. In the same way the 

 seed of N. Tahacuni var. macrophylla showed, on the average, maximum 

 germination on the seventh day. Table II shows that for five-year-old 

 seed of five N. Tahacuni varieties three gave maximum germination on 

 the eighth day, one on the eleventh, and one on the fifteenth, while of 

 two varieties of N. rustica one showed the greatest amount of germi- 

 nation on the fifth and the other on the eighth day. With reference, 

 further, to these N. rustica varieties (16/07 and 17/07) as shown in 

 Table II &, seed of three different ages germinated most heavily on the 

 fifth day, while seed of four dift'erent years of 16/07 germinated, on 

 the average, later during the germination tests. Both the total amount 

 of germination and the length of time during which significant germi- 

 nation took place varies more greatly for the different species and 

 varieties used. There seems to be, however, some significant differen- 

 tiation in this latter respect among the varieties of N. Tahacuni and 

 N. rustica. Thus seed of 17/07 completes its significant germination 

 in a shorter space of time than does 16/07. Similarly 78/05 and 

 110/05 exhibit, on the average, a greater duration of germination than 

 does the seed of the other N. Tahacuni varieties. 



As will be seen by a reference to the earlier communication (1913, 

 p. 215), certain apparently significant facts were revealed when the 

 germination of parental vs. hybrid seed, through a number of 

 generations, was tested and the results compared. The first part of 

 Table V expresses in condensed form the data given in the earlier 

 paper {I.e., p. 216). H 18 represents the cross 110/05 X 78/05; H 20 

 its reciprocal. The striking difference between the results of the ger- 

 mination test carried out with 1909 78/05 in 1913 and the one made 

 with the same seed in 1914 will be explained by reference to the earlier 

 paper (I.e., p. 221). As may be seen, H 18 and H 20 are not signifi- 

 cantly differentiated in any striking fashion with reference to the 

 duration of germination and as to the day during the extent of the 

 test upon which the maximum anumnt of germination took place. 

 The average total amount of germination of the parents, including 



