1921] SCHERTZ—MOTTLING 97 
potting soil for repotting. Plants of type B were taken from the 
same group as A, and were repotted in pots of the same size as A, 
but sand was used instead of soil. In this way the plants were 
grown under exactly the same conditions of light and moisture as 
were the plants of type A, but the amount of soil nutrient was 
considerably reduced. The larger plant in each figure (figs. 5, 6) 
is of type A. The two plants shown in fig. 6 were grown in 6-inch 
pots, while those in fig. 5 were grown in 8-inch pots. All the 
leaves designated “green” were picked from plants of type A, 
and the “mottled” leaves were picked from both sets of plants 
and were analyzed separately. The mottled leaves from plants 
of type A as a rule were only partially mottled, while those from 
type B were always completely mottled. The green leaves were 
picked from the plant 3 or 4 nodes above the yellowing leaves, 
TABLE V 
MAGNESIUM 
; le | Per i 
Le same | Sample | Sample | avenge |i cn 
NS Ee ee ee 0.0922 0.0980 0.0952 0.0951 1.50 
Monee Ae 0.0883 0.0892 0.0035 0.0903 1.66 
Moen Be 0.0938 0.0740 | 0.0840 | 0.0839 1.35 
and the mottled leaves from types A and B were picked just 
about the time they were ready to fall. The leaves were always 
Picked before 8:00 A.m. in order that the results might better be 
compared. 
The amounts of magnesium and calcium were determined 
according to the methods given in Bulletin 107 of the Bureau of 
Chemistry (8). In each case 40 gm. of green material was used for 
the determinations, and the results are given in grams of the 
free element per 100 gm. of wet material. The leaves were dried 
at 100° C. before being analyzed, and the dry weights found were 
used in calculating the grams of calcium and magnesium per 100 
gm. of dry weight. 
The magnesium content of mottled Coleus leaves differed 
little from that of green ones, and the magnesium content of both 
was somewhat higher than that reported for other leaves. As 
calculated from table V, the ash of green Coleus leaves was 17.5 
