19--] Setchell-Goodspeed-Clausen : Nicotiana Tahacum 469 



In general, then, a survey of F^ shows throughout a series of ten 

 different families a uniformity of individuals as great as that exhib- 

 ited in either of the parents. Some few slight differences exist among 

 individuals both of F^ and of the parents which may possibly be re- 

 ferred to lack of a completely homozygous conditon in the parents. 

 In characters in which the two parents differ, whether in color of 

 flower, quantitative corolla character complexes, capsule character com- 

 plexes, or leaf character complexes, the F^ hybrid exhibited through- 

 out a character expression intermediate between that of the two 

 parents. 



3. r, OF THE ANGUSTIFOLIA-MACKOPHYLLA SERIES 



In 1911, there were selected as parents for the F^ 13 plants from 

 Ho and 12 from H^. Twenty-one families of approximately 50 plants 

 each were set out in the field. On account of the great diversity shown 

 in these populations, it was found impossible to study individually 

 each of the thousand plants grown ; consequently particular attention 

 was paid to only 5 families from each hybrid. The other families wore 

 gone over carefully, but nothing notably different w^as found in their 

 behavior. All fifty plants survived in each family except in the last, 

 viz., llFoH^P^g, where only 48 came to maturit3^ There were then 

 498 plants of Fo under more careful observation, representing both 

 the cross and its reciprocal, with about 550 remaining for only casual 

 examination. 



As might have been expected, there was a great variety of plants 

 resulting and segregation as to differences in combination of characters 

 of flower, fruit, and leaf was little short of bewildering. An attempt 

 was made to study and arrange these combinations, but it was found 

 to be impossible. A careful survey, however, was made of the popu- 

 lations and a tabulation of characters was attempted. Some 16 fairly 

 readily separable types, based on leaf characters, were distinguished, 

 but between these closely approaching types others were to be found 

 of intermediate and overlapping character. One each of the types 

 selected was drawn, and these drawings are reproduced in plates 63 

 to 78. 



A glance at these plates, which were carefully drawn to scale, will 

 show something of the nature of the combinations of characters of the 

 two original parents. Type 1 (pi. 63) shows a close approximation, 

 yet not an absolute reproduction, of angustifolia, while type 16 (pi. 78) 

 in a similar way is a close approximation to macro pkylla. The other 



