In the northeastern United States, fern rachises https://ru.wikipedia.org/wiki/Fern rachises are very popular, only during the short season. Like the Matteuccia (ostrich) , which we eat before being linked to cancer. There are suspicions about Pteridium (bracken), which grows in California.
The fern contains ptaquiloside, a strong carcinogen,) it was isolated from the bracken fern or Isusova grass,) it was isolated from the bracken relatively recently. The main countries where ferns are eaten are Korea and Japan, it is assumed that the high incidence of bladder cancer in these countries is associated with the consumption of ferns, but this is still only a version. In many countries, fern is a valuable vegetable crop; in terms of biological value, the proteins of the bracken fern are close to the proteins of grain products (which are considered easily digestible), and mushrooms, but inferior to proteins of animal origin. Fern contains a large amount of vitamins, good mineral composition and a lot of dietary fiber, useful amino acids. Raw fern is considered a conditionally poisonous plant; it usually undergoes heat treatment (boiled) before being eaten. The studies carried out have proven the destruction of ptaquiloside during heat treatment. It should be taken into account that the fern contains a substance called ecdysterone, which has a stimulating effect, lowers blood cholesterol, inhibits (inhibits) the growth of sarcoma cells and some cancerous tumors.
I sometimes eat fern, pick it myself in the spring, it tastes like asparagus, it is very good in Korean salads. Of course it is your choice to eat it or not.