532 Length of the Fruit in Oenothera Lamarckiana. 



five good fruits as a measure of the length of fruit in 

 each individual. 



The reasons which led me to this choice are the fol- 

 lowing. My selection was always an individual one ; 

 that is to say I did not search for the longest and shortest 

 fruits in the harvest, but for the individuals the mean of 

 whose fruits was the longest, and for those the mean of 

 whose fruits was the shortest. But on each inflorescence 

 the size of the fruits gradually decreases from below up- 

 wards with the gradual exhaustion of the plant. Lateral 

 branches often have small capsules ; but as a rule I did 

 not allow these to develop ; I simply broke them off quite 

 young. For that was the only way in which it was pos- 

 sible to grow a large number of healthy plants on the 

 relatively small space at my disposal. 



The mean length of the five lowest fruits is obviously 

 more or less an arbitrary measure of the mean length 

 of the fruit of a plant. It would be more accurate to 

 measure ten or twenty fruits. We cannot count, with 

 sufficient certainty, on more than twenty ripe fruits per 

 plant; many individuals do not bear so many; for the 

 flowers which open after the first of September usually 

 do not ripen their fruits with us. To measure the mean 

 length of all the fruits on a plant, all the lateral branches 

 would have to flower, and measurements would have to 

 be made of the ripe fruits of all the flowers. But this 

 is absolutely impossible ; at least in our climate, and when 

 the plants are cultivated as annuals. 



Fortunately the measurements of the five lower fruits 

 gives figures the accuracy of which is sufficient for our 

 experiment. In order to prove this statement by a direct 

 experiment I took 2>d> plants in November 1 893 and meas- 



