Passage
1 Ferns were once thought to be magical plants. That’s because they bear neither flowers nor fruit nor seeds, yet a new plant emerges, seemingly out of nowhere. We now know that ferns grow from spores, but there was a time when it was believed they did bear flowers. According to a legend, ferns bore flowers before the birth of Christ. When Jesus Christ was born, the plants around his birthplace burst into bloom in celebration, with the exception of the ferns. For this failure, ferns were condemned to a flowerless state from that day on.
2 According to another legend, ferns flowered only at night. The flowers which were said to be of beautiful blue color, opened very quickly and just as quickly faded, which was why no one ever saw them. The flowers were then replaced by golden seeds that ripened by midnight, but as no one had ever seen a fern seed, it was thought that they were invisible, like the flowers.
3 It was believed that possession of the invisible seeds would also make one invisible. Consequently, many devious plans were devised to secure the valuable fern seed. One plan involved 12 pewter plates stacked on top of one other and held under the fern plant at midnight on St John’s Eve (June 24), the only time the invisible seeds would ripen and fall from the plant.
4 According to the legend, the falling seeds would pass right through the first 11 plates before landing on the 12th. Only then could they be obtained---- if one was careful enough. More often than not, however, the slightest gust of wind would blow them away, so if the collector did not become invisible afterwards, he would know he had failed to secure the invisible seeds.
5 As late as the 1800s, some scientists insisted that ferns must have flowers and seeds like any other plant. It was only later that they realized ferns propagated by spores, which differ from seeds in that they consist of a single cell. Seeds, on the other hand, consist of many cells and contain young underdeveloped plants. It is almost magical how a tiny seed can grow into a huge tree. But it seems there are plants that are more magical than others.
What is the main idea of this passage?