Phylogenetic anatomy of the Cretaceous Cycadophytes.

我们对白垩纪苏铁植物进行了解剖学研究，作为阐明被子植物起源的基础。1）西田春文对产自北海道和千叶县的本内苏铁目植物的花进行了组织学和器官学研究。(1)He研究了苏铁总科（Cycadeoidea）和苏铁属（Cycadeoidella）的花的结构，阐明了斑叶苏铁目（Bannettitales）的胚珠被一层单细胞鞘所包裹。(2)He在苏铁属的珠被中发现了维管束，这在本内苏铁目中还没有发现。(3)He还观察了苏铁属聚囊壁中的维管束，这在本目中也是未知的。(4)He提出了一个新的器官分类假说，即Bennettitales的合囊壁和胚珠鞘起源于Bennettitales叶的小羽片的末段（Nishida，H.，1991年）。2）NISHIDA，Makoto已经检查了解剖。白垩纪苏铁植物的一些营养器官。(1)He对来自北海道的四种苏铁类树干进行了组织学研究，此外，他还描述了来自群马县的一种大苏铁树干作为一个新属（Nishida et al.，1991年）。(2)He他还研究了一个来自北海道的石化叶柄和一个细长的树干，它们非常类似于活的苏铁。这些发现是日本首次发现石化苏铁。

We have examined anatomy of the Cretaceous cycadophytes as a basic studies to elucidate the origin of angiosperms. 1)Nishida, Harufumi has studied histology and organography of flowers of Bennettitales from Hokkaido and Chiba Prefecture. (1)He has examined exact structure of flowers of Cycadeoidea, a big member of the order, and Cycadeoidella, a small member of the order, and elucidated that the ovules of Bannettitales are enveloped by a one cell-layered sheath. (2)He found out vascular strand in the integument of Cycadeoidella, which has never been examined in Bennettitales so far. (3)He also examined vascular strand in the walls of synangium of Cycadeoidella, Which has also never been known in this, order so far. (4)He has proposed a new organographycal hypothesis that the walls of synangium and ovular sheath of Bennettitales originate in ultimate segments of pinnules of bennettitalean fronds(Nishida, H., 1991).2)NISHIDA, Makoto has examined anatomy of. some vegetative organs of the Cretaceous cycadophytes. (1)He has reviewed histologically four species of cycadeoidean trunks from Hokkaido, and in addition, he described a big cycad trunk from Gunma Prefecture as a new genus(Nishida et al., 1991). (2)He also examined a petrified petiole and a slender trunk from Hokkaido, which closely resemble living Cycad. These findings are the first records of petrified cycads in Japan.