How are they? The ferns and horsetails have widely varying forms including prostrate, erect, climbing, epiphytic and aquatic. The ferns can be distinguished by the division of their fronds (pinnate, bipinnate). The horsetails are evergreen shrubs with segmented stems that resemble those of reeds. Twigs emerge from each segment like spokes on a bicycle wheel. The club mosses and selaginellas are small creeping plants.
How do they live? The ferns and related plants have two life cycle stages: the sporophyte and gametophyte. The sporophyte is the stage we commonly recognize as a fern.
It has large fronds (primitive leaves) that may be pinnate, bipinnate, tri- or tetra-pinnate (by the number of divisions). Some of the fronds have sori, which are the structures where spores are produced. These spores are wind dispersed and give rise to the second stage: the gametophyte, which is poorly known due to its small size of less than 2 cm. This tiny heart-shaped plant, known as a "prothallus", has female (archegonia) and male (anterioridios)sex organs on its lower structure, and is the stage in which sexual reproduction occurs.
How do we use them? They are cultivated primarily as ornamental plants. In many places ferns are sold to decorate houses. Tree ferns have been heavily impacted because their trunks, known as "maquique", have been utilized as a substrate for orchids.
How can you help? Several species of tree fern(Cyathea costaricensis, Nephelea Mexicana, Dicksonia regalis, D. schiediei),sword fern (Nephrolepis cordifolia)and selaginella(Selaginella porphyspora)are considered in Danger of Extinction and
various ferns, club mosses and psilotums are Threatened. Do not buy ornamental plants if you do not know their legal origin. Do not buy maquique.