Why can’t lichens grow in caves? How can one prove by the structure of a fern that a fern does not bloom?

Lichens cannot grow in caves for one reason – there is no sunlight there. Lichens are a symbiosis of fungi and algae. Algae synthesize and provide energy. They can easily live on rocks without soil, and also absorb water from the entire surface of their bodies. But the lack of a key ingredient in photosynthesis makes it impossible for lichens to grow in caves.

The fern does not bloom as it consists of foliage, stem and rhizome. This plant does not have any other organs, respectively, and the flower has nowhere to come from.