Abstract
1. The length and diameter of the stem, the weight of the whole plant and the yield of fibres, and also the proportion of the fibre to the bark (epidermis, cortex and phloem) increased with the growth, but that of the fibre to the stem began to decrease at 14th week of growth. These phenomena might be caused by speedy growth of woody parts compared with that of bast fibres. 2. During the early life of the plant, new internodes needed three or four weeks, to elongate to full length after the emergence of the node which it followed, but later when the growth were vigorous, two or three weeks were needed. 3. The thickness of the stem and its woody part at a definite part (the 2nd internode) continued to enlarge with plant growth, but the thickness of the bark and bast fibrous layers and the numbers of both fibre layers and bundles increased till 12th week (the time of florescence), and thereafter only slightly or scarcely increased. The proportion of the bark to the stem decreased with growth and also that of the fibre layer to the stem decreased slightly after florescence. As above-mentioned, these phenomena were caused by the growth being larger in the woody part than in the bark and the fibre layer. As for extention of fibrous tissues, the proportion of it in the stem became larger in the lower part than in the middle and upper ones. 4. The process of formation of fibrous layers varied with their positions in the stem; in the lower part it was earlier, and in the upper part it was later, and also the shape of fibre bundle varied with its location in the stem. 5. All of the fibre bundles in each layer differentiated within one or two weeks and the number of them seemed larger in the layer of higher order and in the upper part of stem. Also the number of cells in the largest bundle in each layer showed the same tendency mentioned above. 6. It seemed to take one or two weeks for thickening of bast fibre cell-walls. The thickness of fibre cell-walls and the dimensions of fibre cells varied little with its layer-order (F1, F2············Fn). 7. Dry weights of stem and fibre were heavier in the lower part, and lighter in the upper part. 8. Distribution of fibrous tissue in the stem became to be uniform as the stem developed. 9. Percentage of fibre was the largest in the part 20 to 40 cm. above the cotyledon-node, and smaller both in the lower and the upper parts. 10. In the upper half part of the stem there were merely three layers of bast fibre, two layers of wood fibre and only one layer brought to completion of both bast and wood fibres at the last stage.
