[Vol. 2 



264 



ANNALS OF THE MISSOURI BOTANICAL GARDEN 



close pollination, a strong individual of the original being 

 similarly enclosed for purposes of control. Conditions being 



favorable for a minute comp 



of these plants with 



the parental type, colored illustrations of flow 



and bud 



and diagram of structure were prepared. The inequality of 

 the leaves was recorded by direct prints. The dimensional 



relations noted above 



The readiness with 



which the leaves flag was noted and in these organs, as well as 

 in the stems, it was seen that rigidity is maintained by tur- 

 gidity rather than by stiffness of the mechanical tissues. The 

 development of the bast-fibers is less marked in the derivative, 



Fig. 2. Lower line shows outline of angle of stem of parent Scrophularia; 

 upper line outline of same feature in derivative. 



and a similar deficiency of wood-formation is noted. A cor- 

 respondent difference is apparent in the wings of the angles 

 of the stems, which are thick with their sides parallel in the 

 original, while in the derivative these decrease in thickness 

 gradually toward the margin, with the effect in cross-section 

 seen in fig. 2. The actual value or importance of these dif- 

 ferences is not a matter of moment in the present connection. 

 The chief interest lies in the fact that recognizable effects have 

 been produced by the introduction of foreign substances into 

 ovaries and that the differences shown by the first generation, 

 Fi, are borne by the second generation, F 2 . The original ob- 

 servations with the plant in which this was demonstrated 



