1920] BRIEFER ARTICLES 155 



On August 10 ten of the tallest plants remaining in each pot were pulled 

 up and weighed, with the following average results per plant: 



Pot 



Weight 



A (darkened) 852 mg. 



B 



1 160 



C (darkened) 822 



D 



1712 



These were the last observations made during 1916; no opportunity- 

 occurred to continue the work in 1917. In 1918 four 10-inch pots were 

 again used, those labeled A and C being darkened, while B and D remained 

 uncovered. As pots A and B were sown and examined on different 

 dates from C and D, the data for each pair will be given separately. 

 In both sets the pots were darkened during the morning only; on 

 two out of every three days on which the plants were shaded the sun 

 was shining at the time. 



Pots A and B were sown with flax on May 7. On June 12, 29 of the 

 tallest plants were left in each pot, the others being removed. Pot A 

 was darkened altogether 34 hours and 53 minutes on 15 days, from 

 June 12 to 29. On July 2 nine plants were in flower in each pot, and 

 seeds were ripe in each on July 25. On July 27 all the plants were 

 pulled up, measured, and weighed with the following results: 



Average 

 p Average Average number op 



LENGTH WEIGHT CAPSULES 



PER PLANT 



A (darkened) 514 . 6 mm. 1 136 mg. 4 . 6 



B 5 260 I2 36 55 



Pots C and D were sown on June 8. On July 4, 36 plants were left 

 in each pot. Pot C was darkened for 43 hours and 30 minutes on 

 18 days, from July 4 to 25. On July 25 two plants were in flower in 

 C and six in D, while in both the first seeds were ripe on August 15. 

 On this date the ten best plants in each pot were pulled up, measured, 

 and weighed. The results are as follows: 



Average 



p Average Average number of 



01 LENGTH WEIGHT CAPSULES 



PER PLANT 



C (darkened) 43 1 . 5 mm. 1 248 mg. 5 . o 



D 530.5 2397 6.5 



Summary and conclusions 



1. Flax plants were raised in 10-inch pots placed in the open and sunk 

 in the ground up to the brim. 



