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在光学显微镜及扫描电镜下，比较观察了红豆杉科Ｔａｘａｃｅａｅ５属即红豆杉属Ｔａｘｕｓ、白豆杉属Ｐｓｅｕｄｏｔａｘｕｓ、穗花杉属Ａｍｅｎｔｏｔａｘｕｓ、榧树属Ｔｏｒｒｅｙａ和澳洲红豆杉属Ａｕｓｔｒｏｔａｘｕｓ８种植物茎次生韧皮部的结构。其主要结果为：红豆杉科植物茎次生韧皮部由轴向系统和径向系统两部分构成。轴向系统由筛胞、韧皮薄壁组织细胞、蛋白细胞及韧皮纤维组成；径向系统由韧皮射线构成。但是，在横切面上，各个组成分子的层次有所差异；韧皮纤维的形状、大小、数量、结晶的有无以及结晶的形状等都有所不同。这些可作为本科分属的鉴定特征，也为科内分族提供了佐证。需要强调指出的是，除澳洲红豆杉属外，其余４属的韧皮纤维外壁均具草酸钙结晶，而且结晶的形状、大小和频率均有所不同。根据这些特点可以把红豆杉科分为四个族，从原始到进化的顺序是：第一个族红豆杉族（包括白豆杉属和红豆杉属）；第二个族是澳洲红豆杉族（澳洲红豆杉属）；第三个族是穗花杉族（穗花属）；第四个族是榧树族（榧树属）。
Under the light microscope and scanning electron microscope, we compared the secondary phloem of the Taxaceae 5 species, Taxus, Taxus, Pseudotaxus, Amentotaxus, Torreya and Austrotaxus structure. The main results are as follows: The secondary phloem of Taxus plants is composed of two parts: axial system and radial system. The axial system consists of sieve cells, phloem parenchyma cells, protein cells and bast fibers; the radial system consists of phloem rays. However, the cross-section, the composition of the various levels of different molecules; bast fiber shape, size, number, the presence of crystallization and the shape of the crystal are different. These can be used as a subordinate identification characteristics, but also provide evidence of tribal clan. It should be emphasized that, in addition to Taxus, the four outer bast fiber outer walls are calcium oxalate crystals, and the shape, size and frequency of crystallization are different. According to these characteristics, Taxaceae can be divided into four groups, from primitive to evolutionary order: the first taxa family (including the genus Taxus and Taxus); the second family is Taxus Australis (Taxus australis); the third is a flower group (genus Pinus); and the fourth is a tree family (tree).