592 
Journal of Agricultural Research 
Vol. XXXI, No. 6 
The measurements given in Table III bring out the same facts 
as those recorded in Table II. Under normal day the internodes of 
the annual were generally longer than those of the biennial (pi. 3) r 
but this difference tended to disappear under longer illumination 
although, even in the older seedlings, the internodes of the annuals 
always averaged somewhat longer than those of the biennials. This 
is true of the first as well as the subsequent internodes (pis. 4 and 5). 
In the winter of 1922-23 this work was repeated, the following lots 
of seed being used: 
2062. Common biennial. 
*2066. Grundy County biennial. 
"2143. M&e'd annual. 
12044. Late annual. 
12001. Early annual. 
12056. Late annual. 
The seeds vjere sown November 16, and some were measured 
January 10, 55 days from sowing; others January 25, 70 days from 
sowing. Those of the first set were nearly all two-leaved, those of 
the second nearly all three-leaved. Both sets of figures are given 
in Table IV: 
Table IV .—Average length of first internode , average stem lengthy and average 
internode length of two~leaved seedlings measured 55 days and of three-leaved 
seedlings measured 70 days after sowing on November 16, 1922 
[Measurements in millimeters. Lettering as for Table II] 
2-leaved (55 days) 
3-leaved (70 days) 
Biennial 
Annual 
Biennial 
Annual 
2062 
2066 
2143 
12044 
12001 
12056 
2062 
2066 
2143 
12044 
12001 
12056 
rr_ 
6.2 
4.7 
6.6 
9 
5.7 
4.3 
5 
2.3 
5.8 
7 
5.7 
5.3 
NF..- 
s_ 
10.7 
6.4 
11.5 
14.7 
12.1 
8 
10.6 
6 
17.4 
17 
24.5 
13.7 
i_ 
2.2 
.8 
2.5 
2.8 
. 3.2 
1.8 
1.5 
1.2 
3.9 
3.3 
6.3 
2.8 
ri # .- 
6.6 
4.3 
8.6 
9.4 
7.1 
6.8 
8.4 
5 
7.4 
9.4 
8 
6 
N_• 
s.... 
15 
6.9 
18.2 
18.4 
17.3 
14 
21.8 
10.2 
24 
28.4 
29 
22.2 
i_ 
4.2 
1.3 
4.8 
4.5 
5.1 
3.6 
4.5 
1.7 
5.5 
6.3 
7 
5.4 
rr_... 
6.4 
4.3 
8 
11.7 
6.5 
6.4 
8 
3 
6.4 
8 
7 
6.1 
S....- 
s_ 
10.6 
6 
15 
29 
14.2 
12.4 
17 
4.7 
13.4 
17.4 
23 
15 
i_ 
2.1 
.8 
2.5 
8.6 
3.8 
3 
3 
.6 
2.3 
3.1 
5.3 
3 
r_ 
16.5 
12.3 
15.5 
22.4 
13.4 
12.1 
15 
11.6 
15 
23 
14 
13 
L....- 
s. 
35 
28 
35 
46.8 
29.9 
26 
37.6 
39 
49.3 
65 
48 
45 
i_ 
9.2 
7.8 
9.8 
12.2 
8.3 
6.9 
7.5 
9.1 
11.4 
14 
11.3 
10.7 
All flats were in a center bench, some 6 feet below the glass, and it 
was suggested that if the seedlings, under normal day, were nearer 
the glass, the stems might be shorter. To test this, one set of flats 
was placed on a frame raised so as to bring the surface of the soil 
within 8 or 9 inches from the glass. In Table IV, the measurements 
of the seedlings taken from these flats are given under NF. 
As between the seedlings, under normal day, from the center bench 
and those from the raised bench, the length of the first internode does 
not show any consistent difference in the younger seedlings, but does 
in the older ones. In the three-leaved seedlings the first internode 
of those from the raised bench is regularly and noticeably shorter 
than in those seedlings growing farther from the light. This feature 
comes out more prominently when the stem lengths of the two sets 
