16,6 Trelease: The Growth of Rice 609 
allowed to become air-dry, after which the final weighings were 
made. 
EXPERIMENTAL RESULTS 
APPEARANCE OF THE PLANTS 
The plants in all of the cultures made vigorous growth. 
Within a week after transplanting many of the cultures were 
observed to be growing more rapidly than the control cultures, 
and these differences became more marked as the experiment 
continued.^ Although the plants that had received fertilizer 
grew more rapidly than those of the control cultures, even the 
latter made rather good growth and appeared nearly as vigorous 
as plants growing in the field. Besides these differences in rate 
of growth, differences in color were noted, these becoming con- 
spicuous about three weeks after transplanting. At this time 
the cultures having 0.1 and 0.2 of their total osmotic concentra- 
tion due to ammonium sulphate were small and were light green 
in color; those having 0.3, 0.4, and 0.5 due to ammonium sul- 
phate were a medium shade of green; and the cultures having 
0.6, 0.7, and 0.8 of their total concentration due to this salt were 
a very dark shade of green. The plants that were medium and 
those that were dark in color were apparently the most vigorous 
and made the most rapid vegetative growth ; they also produced 
the largest numbers of stools and the broadest leaves. It is 
thus suggested that the greenness and breadth of the leaves 
and the number of stools were roughly proportional to the am- 
monium sulphate content of the fertilizer mixture. These dif- 
ferences in color remained noticeable until several weeks after 
the time of flowering, when all of the cultures became yellower in 
color and the differences became less marked. 
Flowering began in the first week in September. There was 
no very great difference between the various cultures in the time 
of flowering. Within a week after the first flowers appeared 
most of the plants had developed flowers, and within two weeks 
all of the plants were in bloom. 
MEASUREMENT OF PLANT GROWTH 
In order to obtain an approximate measurement of the rates 
of growth, the height of the tallest leaf in each plant was meas- 
ured at weekly intervals. These measurements need not all 
be presented here, but those made on September 17, when most 
of the plants had reached approximately their maximum size 
and had begun to produce flowers, may be considered. The 
