74 Winifred E. Brenchley . 
Range of variation. 
Mean. 
Grams. 
Grams. 
Wheat+Wheat 
4.63—11.95 
7.365 + 0474 
Wheat +_Spergula 
4.01— 8.65 
7.037 + 0.340 
Spergula + Spergula ... 
0.44— 0.83 
0.579 + 0.025 
The weight of the spurrey plant is obviously almost negligible 
in the wheat and spurrey, as the latter did not develope very far, 
ceased growing early in the experiment, and died off before 
harvesting. Consequently the wheat did not suffer any very great 
initial check, and as soon as the competition factor of spurrey was 
virtually removed, the wheat took advantage of the fact, so that 
the individual plants of wheat with spurrey showed a gain of 
about 90% over the wheat which had mutual competition of wheat 
all along the line. It seems evident that the spurrey cannot have 
exercised any other appreciable influence than that of mere com¬ 
petition at the beginning, as if any such action had been at work to 
any degree the wheat could not possibly have gained so much 
ground. 
Wheat and Alopecurus agvestis. 
Wheat seed graded 0-06—0-07 gram. Sown April 7th. 
Alopecurus agrestis sown April 3rd. 
Plants put into solution April 18th. 
The wheat grew well from the beginning to the end of the 
experiment. Some slight etiolation appeared in all plants in about 
three weeks, but this was soon remedied by the addition of 
additional ferric chloride. 
Alopecurus started well, but within three weeks the plants 
associated with wheat appeared rather less strong than the others, 
and before the end of the experiment they were quite dead. The 
double plants, however, remained strong and healthy to the end, 
though they exhibited considerable variation. As with spurrey, 
the plants could not be separated when harvested. 
Range of variation. Mean (per bottle) 
Grams. 
Grams. 
Wheat+Wheat 
3.21—8.43 
6.107 + 0.416 
Wheat + Alopecurus 
3.31—6.74 
4.973 + 0.247 
Alopecurus + Alopecurus ... 
0.30-1.59 
0.908 + 0.093 
