8o8 
Journal of Agricultural Research 
Vol. XXI, No. li 
x this equation is appreciably better than equation I. However, for 
purposes of extrapolation beyond the upper range of observations, equa¬ 
tion II may be considered the more conservative, as shown by the calcu¬ 
lated results. The parabola obtained from equation I is very close 
indeed to the observations for the upper limits of the range, and perhaps 
this equation would give more accurate results for extrapolation pur¬ 
poses when calculations are made beyond the range. The extrapolated 
values would be the greater for equation I. 
APPLICATION OF EQUATIONS 
Assuming that either equation I or II is sufficiently correct for practical 
purposes, one may say that each represents or formulates the law of the 
rapidity of culm formation in Broinus inermis under the conditions indi¬ 
cated. These are: (i) Culm formation during the first or seediing year; 
(2) free from competition; and (3) under favorable soil and moisture 
conditions. The equations could, no doubt, be applied to certain other 
perennial grasses of similar growth with only slight modifications. Cer¬ 
tainly they would need to be modified somewhat when applied to Bromus 
inermis grown under conditions other than those cited in this study. 
These equations serve the purpose of indicating, at some future period 
for the plants under study, the amount of growth in number of culms 
produced, with all conditions remaining constant. It is true enough 
that conditions would not remain constant for any considerable future 
period for the reason that the season of seed maturity, for example, 
from the standpoint of the plant and the winter season of dormancy 
from the standpoint of environment intervene and profoundly modify 
culm formation. 
It is a matter of value as well as of interest to compute the theoretical 
future rate of culm formation and see if there is any comparison within 
reason between the theoretical and the actual rates. Such a comparison 
might throw some interesting sidelights on the problem of deterioration 
of stand in brome-grass meadows. 
EXTRAPOLATION 
The method of extrapolation is simplicity itself, as one has merely to 
insert the proper value of x in the equations to secure the theoretical 
number of culms at any future period. The theoretical number of culms 
for a period of one year’s steady growth will be found, and to do this 
x will have to be assigned the value of 322. This gives the number of 
culms at the specified time as 2,213, an increase of 2,097, or over 1,800 
per cent, since the last actual count made September n, 1916. An 
inspection of figure 1 indicates there would be a very rapid rate of increase 
after this date. 
