博士，昨天爸爸带我去了植物园，原来世界上有这么多种植物。地球上被发现的植物已有40余万种啦。可惜有些植物很稀少了。老师和我们讲起过很多珍稀的树种，水杉啊，珙桐啊……水杉是我国科学家直到1943年才发现的，它是亿万年前就在地球大陆生存过的一种植物，后来各洲的水杉 Dr. Daddy took me to the botanical garden yesterday. There are so many plants in the world. More than 400,000 species of plants have been discovered on Earth. Unfortunately, some plants are rare. The teacher and we talked about a lot of rare tree species, Metasequoia, A. Indole...... Amethyst was discovered by Chinese scientists only in 1943. It was a plant that had survived on the Earth’s continent hundreds of millions of years ago. Metasequoia