Filicales

Filicales is an order of ferns, commonly referred to as the leptosporangiate ferns. This group represents the vast majority of living ferns and is characterized by the development of their sporangia, which arise from a single epidermal cell. This contrasts with the eusporangiate ferns, where sporangia originate from multiple cells. Filicales are found worldwide, inhabiting diverse environments from tropical rainforests to temperate woodlands and even some arid regions.

The life cycle of Filicales, like all ferns, involves alternation of generations. The dominant, leafy sporophyte plant produces spores in sporangia, typically located on the underside of the leaves in structures called sori. These spores germinate to form a small, heart-shaped gametophyte, also known as a prothallus. The gametophyte produces gametes, which fuse to form a zygote that develops into a new sporophyte.

Within the Filicales, there is considerable diversity in growth forms, ranging from small epiphytes to large tree ferns. Leaves, or fronds, can be simple or highly divided. Many species are important components of their ecosystems, contributing to soil stabilization and providing habitat for other organisms. Some species have historical and cultural significance, being used in traditional medicine or as ornamental plants. The classification of Filicales is subject to ongoing research and revision based on molecular phylogenetic studies.