蕨类植物门是植物界中的一门，约有两万个左右的物种，属于维管束植物。

蕨类植物（羊齿类植物）比起较原始的石松门多了真正的叶子，但比起较进化的种子植物（裸子植物和被子植物）则缺少了种子。和所有的维管植物一样，蕨类植物有着一个世代交替的生命周期，由双套的孢子体和单套的配子体两者循环着。和裸子植物与被子植物不同的，配子体是一游离的器官。蕨类植物典型的生命周期如下：

A fern is a member of a group of about 12,000 species of vascular plants that reproduce via spores and have neither seeds nor flowers. They differ from mosses by being vascular (i.e. having water-conducting vessels). They have branched stems and leaves, like other vascular plants, but these are megaphylls, more complex than the simple microphylls of clubmosses. Most ferns have what are called fiddleheads that expand into fronds, which are each delicately divided.