1915] 



MACDOUGAL — MODIFICATION OP GERM-PLASM 261 



whole blade was more oblique in outline. The elongation of 

 the lamina had been checked and the ratio of width to length 

 of the leaves was greater than in the parental stock. If cor- 

 respondent leaves of rufida and the originals were laid side 

 by side it could be seen that the basal veins on the side away 

 from which the tips were curved were different in the two 

 cases, the derivative showing two strong veins in the place in 

 which one lateral with a thin branch occurred in the original 



(fig. 1). The water relations of derivatives and normal were 



not identical, and when young shoots or branches developed 



Fig. 1. 0, branching lateral vein in parental 8 crophularia ; D, branching vein 

 replaced by two laterals in leaf of modified 8 crophularia. 



under similar conditions were detached, those of the deriva- 

 tives flagged and wilted much more quickly than those of the 

 normal. 



The auxetic departures noted above also extended to the 

 inflorescences, which in the original show a fairly regular 

 basipetal development into thyrses. The derivatives, how- 

 ever, exhibited a rather irregular maturation of clumps of 

 buds and the thyrses were very irregular, not reaching the 

 spread of the parental forms. The fragility of the leaves 

 does not seem to extend to the flowers, which opened very 

 slowly, and in some cases the distended corolla persisted for 

 a few days. The amount of color in the corolla was largely 

 a matter of illumination, but under equivalent circumstances 

 the derivatives always showed less than the parental form. 

 As noted above the color persists to some degree in the deriva- 



