大约３０亿年前，地球上已出现了植物。最初的植物，结构极为简单，种类也很贫乏，并且都生活在水域中。到了４亿多年前，由于气候变迁，生长在水里的一些藻类，被迫接触陆地，逐渐演化为蕨类植物，这是最早登陆地球的植物。 最早的陆地植物主要是裸蕨类。刚登陆时，它们既无 About 3 billion years ago, plants appeared on the earth. The original plant was extremely simple in structure, poor in species, and all lived in water. Over 400 million years ago, due to climate change, some of the algae that grew up in the water were forced to touch the land and gradually evolved into ferns. This was the first plant that landed on the earth. The earliest land plants were mainly bare ferns. At the time of landing, they were neither