亚麻的横向截面形态：多边形或多角形，形态偏圆，中腔较小，大部分呈圆点状。
The shape of flax's transverse section is polygonal or polygonal, the shape is partial circle, the middle cavity is small, most of them are in the shape of circle.
在偏振光下，亚麻的外观形态和纤维细度仪观察的基本相同，但横节更明显。
Under polarized light, the appearance of flax is basically the same as that observed by fiber fineness meter, but the transverse section is more obvious.
纵向颜色特征：亚麻与载物台成+45˚方向时，纤维主体呈粉红色，一侧边缘呈绿色；亚麻与载物台成－45˚方向时，纤维主体呈橙色，一侧边缘呈灰白色。
Longitudinal color characteristics: when flax is + 45 ˚ to the stage, the main fiber is pink and one edge is green; when flax is - 45 ˚ to the stage, the main fiber is orange and one edge is gray white.
横向颜色特征：亚麻与载物台成+45˚方向时，纤维主体偏暗橙色；亚麻与载物台成－45˚方向时，纤维主体偏蓝色。
Transverse color characteristics: when flax is + 45 ˚ to the stage, the main fiber is dark orange; when flax is - 45 ˚ to the stage, the main fiber is blue.