162 
Journal of Agricultural Research 
Vol. IX, No. 6 
healthy and mottled leaves of approximately the same age could be 
obtained. 
As in the preceding determinations, the worst mottled leaves have the 
highest percentage of the mineral elements under investigation; and the 
percentage distribution shows no consistent differences between the con¬ 
ducting tissue and the mesophyll areas. 
Table III .—Analysis of orange leaves in various stages of mottling . Leaves collected 
on fanuary j, jgi6 
Part analyzed. 
Stage of mottling. 
Percentage distri¬ 
bution. 
Percentage on dry sub¬ 
stance. 
Ca. 
Mg. 
P2O5. 
Ca. 
Mg. 
P 2 C> 5 . 
Leaf minus midrib. 
None. 
37 
32 
32 
2. 87 
0.332 
0.500 
Midribs alone. 
39 
39 
35 
3 * 07 
. 401 
. 482 
Leaf stems. 
.do. 
24 
29 
29 
1. 85 
.294 
. 400 
Average of leaves 
* 
and midribs. 
2. $7 
• 367 
.491 
Leaf minus midrib. 
2-4 
50 
44 
49 
2. 28 
• 27s 
• 531 
Midribs alone.. 
2-4 
50 
56 
5 i 
•2. 30 
• 323 
• 551 
Average of leaves 
and midribs. 
2. 29 
.299 
• 541 
Leaf minus midrib—... 
4-5 
43 
Si 
40 
r. 78 
. 267 
.563 
Midribs alone. 
4-5 
57 
49 
60 
2 - 39 . 
. 261 
• 835 
Average of leaves 
- 
and midribs. 
2. 09 
. 264 
.699 
Leaf minus midrib. 
Last (leaves all yel¬ 
30 
37 
32 
2. 66 
*344 
• 530 
low, midribs 
green). 
Midribs alone.... 
.do. 
41 
32 
3. 67 
. 208 
.646 
Leaf stems. 
29 
O 
3 i 
oy 
29 
o* v / 
2. 62 
• V 
.294 
•473 
Average of leaves 
and midribs. 
3 - 17 
. 321 
.588 
Leaves. 
Very spotted; yel¬ 
28 
27 
23 
2. 69 
. 204 
.403 
low spots. 
Do.. 
Green spots; mostly 
34 
42 
31 
3 - 24 
• 319 
• 553 
veins. 
Midribs. 
3 S 
3 i 
46 
3. 68 
. 242 
. 796 
Average of leaves 
and midribs ...... 
. 
2. 97 
. 262 
■483 
The last set of leaves given in Table III was collected in another grove, 
where the mottled appearance of the leaves was much accentuated, the 
boundary lines between the chlorotic tissue and the green tissue being 
very sharp. The mottled spots were cut out and these and the remaining 
green parts, mostly veins, were separately analyzed. The green areas 
contain decidedly more of the elements determined than the yellow spots, 
