62 
Winifred E. Brenchley. 
germinates satisfactorily at any time of the year, so that the season 
of the experiment made no difference to it. By itself good progress 
was made ; with buckwheat very great deterioration was observed. 
Buckwheat and Spergida. 
During the progress of the experiment the spurrey looked quite 
as good when associated with buckwheat as when grown alone, 
and this was corroborated by the dry weights—the advantage being 
on the side of the associated plants. This is the only case so far 
met with in which an associated weed has made better growth than 
when grown alone, but too much weight must not be placed on this 
instance, as the growth of the spurrey was not good, so that compari¬ 
son is not altogether fair or accurate. It does suggest, however, 
that under certain circumstances the association of two species may 
be to the advantage of both—that for some reason it may happen 
that the competition between diverse species is less keen than that 
between plants of one and the same species. 
Experiment 3, 1914. 
Fresh soil was used in this experiment, thirty pots being filled 
with heavy soil from Little Hoos field, mixed with a little sand to 
make it more workable, the other thirty pots being filled with light 
sandy soil specially obtained from Woburn Experimental Station, 
through the kindness of Dr. J. A. Voelcker. Seeds were sown 
on April 17th, wheat being used as the crop plant. Papaver 
and Spergida were grown in the Woburn soil and Brassica and 
Alopecurus in the Rothamsted soil. The same treatment was 
given to the pots as in the previous experiments, any alien weeds 
arising from seeds buried in the soil being taken out as soon as 
observed. At the time of harvesting it was impossible to turn out 
the soil in order to extricate the roots, so the crops were cut off 
close to the surface and the roots were perforce neglected. The 
difference in the growth of the wheat on the two soils was very 
marked ; that on the Rothamsted soil had a greater average length 
of straw and ear, and in addition produced a greater number of 
ears, 55 as against 31 on the Woburn soil. The greatest difference, 
however, was in the dry weight, the Rothamsted soil plants grown 
alone weighing 125 grams against the 99 grams of the Woburn soil 
plants. This result was only to be expected, as the heavier soil 
naturally produces a better crop of wheat under ordinary field 
conditions. 
