4 BULLETIN 169, U. S. DEPARTMENT OF AGRICULTURE. 
viridis * were also more or less common. The nurserymen pulled up 
most of the weeds before flowering, so that it was not possible to 
determine positively the relative frequency of the different grass 
species for each plat. The commonest dicotyledons were MoMygo 
verticiUata, 1 Portulaca oleracea, 1 Amaranthus retrqflexus, 1 A. Jiybridus, 1 
A. graecizans, 1 A. blitoides, 1 and Euphorbia glyptosperma. 1 
INJURY TO PINES BY SULPHURIC ACID APPLIED AT OR AFTER GERMINATION. 
In the following cases sulphuric acid was applied to the beds after 
some pine seedlings had come up. Because of the great irregularity 
of germination in many beds the time of germination can be given 
only approximately. It represents as far as possible the date by 
which enough seedlings had appeared to constitute a fair stand. 
Most of the experimental plats were sown with jack pine. The 
results with this species appear in Table II. 
Table II. — Effect of sulphuric acid on seedlings of jack pine, at Halsey, Nebr. 
Num- 
ber of 
plats 
treated. 
Time of treatment. 
Fluid 
ounce of 
acid per 
square 
foot. 
Volumes 
of water. 
Result. 
("On date of germination 
0.172 
.086 
.086 
.043 
.043 
.043 
.086 
.043 
.043 
.086 
.043 
.043 
.021 
.021 
.011 
.011 
None. 
} 128 
1 256 
128 
I 256 
| 512 
} 1,024 
4 
All killed. 
2 
Nearly all killed. 
[l3 days after germination 
4 
f do 
4 
( More killed than in preceding 
\ experiment. 
2 
Germination, 11.8 per cent. 
2 
Germination, 13.8 per cent. 
2 
Germination, 14.7 per cent. 
Half of the plats in Table II which were given the stronger solu- 
tions were sprinkled lightly with water immediately after each treat- 
ment. This watering had no evident effect in the plats treated with 
the 128-volume solution, but in four plats which received the 256- 
volume solution, followed by sprinkling, the stand of seedlings was 
more than twice as great as on four adjacent plats which were given 
the acid treatment only. 
The results in the plats treated with the 512-volume solution 
indicate that a total of 0.043 ounce of acid per square foot applied 
before germination was complete was sufficient to prevent the appear- 
ance of some of the latest germinating seedlings, while 0.021 ounce 
in two applications had little or no effect. Further tests would be 
necessary to prove that injury can be caused by these very weak 
treatments. 
1 Determinations made bv Mr. P. L. Ricker. 
