36 
T. TADOKORO. 
mature flax stem. The stems used for the observation of anatomical structure 
were those grown on the field, rather thickly sown, according to the usual 
method of cultivation in Hokkaido. 
1. The epidermis is a layer with many stomata; its cells are al way 
elliptical. The outer Avail is almost even and close to the cuticle and more 
resistible than the inner wall. The thickness of the cuticle varies according 
to the height and diameter of the stem. The cuticle has strong resisting 
power against the action of organisms and other physical conditions. 
2. The outer cell of the cortical parenchyma resembles an epidermal 
cell in form but the other cells are so slender that we can easily distinguish 
them from the former. 
3. The phloem-parenchyma consists of 1-5 cell layers and the cells bet- 
ween the fiber bundles have more or less irregular form. The fibers have a 
long, streched, spindle form, with almost sharp pointed ends. A cross section 
of the fiber in the middle part of the stem has an angular form with 3-7 
sides, but that of the upper or lower part of the stem has a round oval form. 
The walls are quite thick and the lumen in the lower and the upper part of 
the stem are large and have many striations and pits. 
4. The xylem portion consists of the vessels, trachids, Avood-parenchyma 
and medullary rays. The diameter of all elements become smaller from inner 
to outer layers. 
5. The pith consists of the thin- Availed cell layers which enclose the - 
large pith cavity in the center of the stem. In the upper part of the stem, 
the cavity is very narrow or completely filled. The cells increase in size from 
outer to inner layer. 
2. Anatomical Changes during Retting. 
Betting AA'as divided into three periods, i. e., the first, the middle and the - 
last and each period covered nearly the same number of days. At the end • 
of the last period, not only the separation of the cambium layer and the isola- 
