420 
I. W. BAILEY 
may be more or less completely neutralized by concomitant changes in 
cross-sectional area. 
Table 2. Pinus Strohus L. 
Date 
Source of Cambium 
Nuclei 
Fusiform Initials 
Age of Tree, 
Portion of 
Plant 
Number of 
Rings Under 
Cambium 
Dimensions (Microns) 
Dimensions (Microns) 
TD 
3/25/18 
36 
Stem 
I 
04 
4-5 
18.6 
3/2 1 /1 8 
8 
68 
8 I 
2090 
2"? 7 
3/9/18 
27 
67 
8.9 
2780 
29.5 
2/25/18 
Branch 
60 
4.6 
830 
20.1 
2/25/18 
12 
60 
9.1 
1950 
27.7 
4/22/18 
Stem 
I 
56 
4-3 
800 
16.3 
3/24/18 
48 
82 
8.9 
3890 
42.2 
4/28/18 
48 
41 
17-3 
4000 
38.5 
3/24/18 
61 
84 
7-9 
3000 
32.0 
3/23/^8 
Large root 
32 
42 
17.2 
2760 
40-5 
3/2/18 
25 
Stem 
I 
56 
6.1 
890 
16.3 
3/2/18 
15 
57 
7-9 
2650 
39.1 
4/22/18* 
19 
71 
6.3 
1700 
23-5 
4/22/18* 
19 
34 
13.6 
1700 
23-5 
5/19/18 
15 
36 
15-3 
2400 
35-3 
6/17/18 
17 
39 
12.8 
3260 
35-2 
7/15/18 
17 
32 
16.3 
2970 
36.8 
8/19/18 
17 
39 
13.2 
2580 
34.4 
10/13/18 
19 
59 
8.3 
I7IO 
29.8 
Basis: Dimensions of cells and nuclei are averages of 50 measurements. 
Italicized figures indicate that the nuclei are from cambial initials which have been 
dividing for some time previously. 
* Both types of "resting" nuclei were present in the same sections, due to the fact 
that certain initials had divided, whereas others were still in the winter condition. 
Although the values in table i indicate that the ratio between cell size 
and nuclear size may remain relatively constant in ray initials of difTerent 
sizes, they show very clearly that this ratio varies greatly in fusiform 
initials of different dimensions and volumes. The nuclei do not elongate 
to any considerable extent as the fusiform initials increase in length. In 
other words, these meristematic cells do not contain very abnormally 
elongated nuclei, such as have been described and figured by Molisch 
(1899) for highly specialized tissue cells of certain monocotyledons. As 
previously stated, the relatively small, centrally located nucleus must, in 
certain cases, extend its energizing influence for several thousand microns 
in order to control processes of growth and longitudinal division in the 
cambial initials of various gymnosperms. 
Boveri (1902, 1905) found that the size of the nuclei in echinoderm 
larvae is dependent upon the number of chromosomes which enter into 
the nuclei, and concluded that "die Grosse der Larvenzellen ist eine Funk- 
tion der in ihnen enthaltenen Chromatinmenge, und zwar ist das Zell- 
volumen der Chromosomenzahl direkt proportional." A few years later 
Gates (1909) showed that Oenothera gigas, a tetraploid mutation of Oe. 
Lamarckiana, is composed of larger cells than the species from which it 
