Sept, i, 1921 
Rate of Culm Formation in Bromus inermis 
805 
season would be of interest but evidently of lesser importance than the 
problem at hand. In the one case the rate of formation of a turf is dealt 
with, while in the other case merely a minor phase of the problem would 
be studied, one relating to the behavior of the plant at the close of the 
growing season. 
The raw data, are not presented because of limited space. In Table I 
are presented the means, differences of the means, medians, and ranges 
for each date. The standard deviations, and consequently the coeffi¬ 
cients of variation, were not calculated, as it was not seen that they 
would serve any useful purpose. It is obvious that the standard devia¬ 
tions and likewise the variations increase with great rapidity as the 
season progresses. Some of the plants stool with much greater rapidity 
than others, with the result that distances between the extreme limits 
constantly increase. 
The means and medians were calculated by arithmetical methods. 
The data were almost necessarily left ungrouped, as the class units 
suitable for the earlier dates would be quite unsuitable for the later dates. 
Table) I.— Means, medians, and extreme ranges of number of culms per plant of Bromus 
inermis at various dates 
Date. 
Mean 
number of 
culms. 
Difference 
of means. 
Median. 
Range. 
Tune 10. 
2.37 
2-35 
I to K 
24 .. 
2.99 
O. 62 
3 -o 5 
I to 7 
, 2 9 .. 
5-07 
2. 08 
5 - 03 
I to II 
July 5. 
9-39 
4 - 3 2 
8. 94 
I to 19 
IO. 
11. 16 
I. 77 
io -75 
4 to 22 
15 . 
13 - 45 
2. 29 
13- 4o 
6 to 35 
20. 
16. 05 
2. 60 
16. 00 
6 to 41 
25 . 
21. 86 
5.81 
21-75 
7 to 46 
31 . 
30 - 52 
8.66 
29-75 
10 to 63 
Aug. s. 
35 - n 
4-59 
34 . 38 
12 to 78 
IO. 
43 - 55 
8.44 
42-75 
17 to 107 
15 . 
53-72 
10.77 
5!-25 
21 to 133 
22. 
68. 46 
14.72 
65. 00 
24 to 171 
26. 
77 - 74 
9. 28 
73.00 
24 to 214 
31 ... 
» 9 - 57 
11.83 
82. 75 
32 to 254 
Sept, s. 
101. 79 
12. 22 
95-33 
39 to 293 
II. 
117. 77 
15.98 
IO6. 5O 
40 to 329 
ANALYSIS OP TABLES I 
From Table I one notes that the number of culms per plant increases 
with more or less irregularity from 2.37 at the time of the first counting 
to 117.77 on September 11, the date of the final count. This irregular 
advance may be ascribed in part to irregularities in moisture and temper¬ 
ature but to a considerable extent to the occasional variation of dates in 
counting. When the means are plotted, the irregularity due to the last- 
