SPOROPHYTE. 9 
near to the stem apex (see table 1) and lengthen rapidly. I have one 
which is 24.5 cm. long and the broken ends were frequently found at a 
distance of 20 cm. from the stem. It is likely that these lengths are not 
much exceeded. The rootlets are generally alternate on opposite sides of 
the primary root-axis, but many exceptions occur. Two rootlets are often 
TABLE 2. found consecutively on one side, and in 
one case five were seen. Successive root- 
Hoots Roots: lets may be as much as 8 mm. apart or 
Dg era | etn eee almost or quite opposite Cfigs. 6, 7, 8; 
table 2). None occur usually within 12 
Stem Stem or 15 mm. of the stem. 
13-5 13.0 Table 2 shows irregularities in alter- 
A 3-5 3:5 — nate arrangement of rootlets on opposite 
3.2 2.0 sides of roots. The figures indicate 
3:5 18 3-3 88 distance in millimeters of each rootlet 
3.5 3-5 3-0 from the one next above it, and columns 
388 1.5 5a és show alternation. 
8.0 4.0 The root-cap is rather long and pointed 
oe re 46 oe (fig. 23). From the initial cell of the 
6.5 2.0 root outward ten rows of cells may be 
3-5 6.5 seen in a strongly developed specimen, 
Root 2. 3.0 five in a slender root of a sporeling. 
re a Outside of these cell-layers a worn-out 
4.0 layer is seen, in the act of sloughing off. 
5:5 6.0 : 
2.5 3.5 The inner layers are small-celled and 
ae a0 0.5 richin protoplasm. The outermost cells 
3-0 Bee are four times the diameter of the inner, 
1.5 ||| but still nucleated. Indeed, small, dense, 
3-3 Root 4. ‘ , F 
4-4 nucleolus-like nuclei are seen even in the 
o3 (2) layer that is shedding. The cap thins 
5-0 2.5 out layer by layer along the sides of the 
xe ue 28 a) root, and the cells become very long and 
5.0 ; 8.0 narrow. The outermost layer persists 
JF some distance above the next inner one. 
No sign of statolith bodies has been 
seen in any part of the root-cap. 
In development, each terminal segment of the root-initial gives rise to 
a single layer of root-cap cells.* The segment divides first by an anti- 
clinal wall parallel to one of the sides of the initial (figs. 10, 11, 26). In 
successive cap segments the first wall of one stands either directly over or 
at an angle of 60° to that of the preceding or following one, and not at 
*In a few cases periclinal walls were seen in three to five or six of the median cells, 
making the segment two-layered at that point (fig. 24). 
