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银杏,也叫白果。是落叶乔木,树干高大,分枝繁多,在植物分类系统上属于裸子植物的银杏科,享有“活化石”之美称。据说是与恐龙同时代的植物,为我国特有的珍贵经济树种。在距今一亿四千万年的远古时代,银杏类植物处于繁盛时期,属种非常多,分布极广,几乎遍及全球,单是在我国发现的银杏类的化石,就有十多个属。后来,由于地球上大面积的气候发生变化,银杏类开始衰退,绝大多数的属种陆续退出了生物界。到了距今二百多万年的时期,地球的北半球又产生了巨大的冰川,银杏家族又遇到打击,许多种类都灭绝了,惟有银杏,经历了漫长的时期,形态构造很少改变,一直延续到今天,成了植物中著名的活化石。银杏在科学研究上十分重要。因为它是一类
Ginkgo, also called ginkgo. Are deciduous trees, tall trunks, a large number of branches in the plant classification system belongs to the gymnosperms Ginkgo family, enjoy the “living fossil” reputation. It is said to be a contemporary plant with dinosaurs, and is a precious economic tree species unique to our country. In the ancient time of 140 million years ago, the gingko plants are in the prosperous period, with very large genera and very wide distribution, almost all over the world. There are more than a dozen genus of ginkgo found in our country . Later, due to the change of climate on a large area of the earth, the ginkgo began to decline, and the vast majority of the genera gradually quit the biological world. By the time it took more than 2 million years ago, huge glaciers were produced in the northern hemisphere of the earth and the gingko clan encountered another blow. Many species were extinct. Only ginkgo has experienced a long period of time with little change in shape and structure. Continued today, has become a famous living fossil plants. Ginkgo in scientific research is very important. Because it is a category