June, 1915.] 
Ray Pits of Conifers. 
549 
TABLE I. 
Number of 
tracheid 
Number of Average Diameter 
pits in microns 
Average Diameter 
squared 
1 
3 4.6 
21. 
2 
6 5. 
25. 
3 
7 3.3 
10.9 
4 
1 3.2 
10.2 
5 
3 3.2 
10.2 
6 
6 3.3 
10.9 
7 
6 3.3 
10.9 
8 
3 3.3 
10.9 
9 
5 2.4 
5.8 
10 
2 2.4 
5.8 
11 
3 2.4 
5.8 
Measurement of the ray pits of Larix laricina through one annual ring. 
TABLE II. 
Number of 
tracheid 
Number of 
pits 
Average Diameter 
in microns 
Average Diameter 
squared 
1 
10 
3.1 
9.6 
2 
10 
3.1 
9.6 
3 
10 
3.9 
15.2 
4 
10 
4.3 
18.5 
5 
10 
2.9 
8.4 
6 
10 
3.0 
9.0 
7 
10 
2.6 
7.0 
8 
10 
2.4 
5.8 
9 
10 
2.3 
5.3 
10 
3 
2. 
4. 
11 
5 
2. 
4. 
12 
4 
2. 
4. 
13 
2 
2. 
4. 
14 
1 
2. 
4. 
15 
1 
4. 
16 
4. 
Measurement of ray pits of Larix occidentalis through one annual ring 
of 16 tracheids; 10-16, late wood; 15-16, so compressed that measurements 
were approximated. 
