Ferns are the most common and best-recognized examples of vascular seedless plants. The leaves of ferns have megaphylls—or leaves with more than one vein and a leaf trace/leaf gap association—which are large and usually subdivided into many lobes. Hence, the ‘finger’ look to a fern plant. Fern fronds, as the leaves are called, typically are dissected and feathery in appearance. However, realize that they do vary quite a bit as far as external structure and form goes. Fern fronds start as croziers or fiddleheads which unfurl into the main leaf form. On the underside of the frond, patches of sporangia can be found. These sporangia are usually in sori, which are clusters; and are sometimes covered by a clear flap called the indusium. This setup allows for the maximum protection of the sporangia, but allows for distribution. Individual sporangia have an ‘spring-loaded’ annulus which allows for mature spores to be catapulted out of the sporangium. The gametophytes of ferns are called prothalli and develop after the spores germinate. Prothalli contain both archegonia and antheridia and only one zygote develops into a sporophyte.
Ferns are used for ornamental purposes as well as stuffing materials for bedding in tropical regions. Fern fronds are used in weaving baskets and hats, brewing some types of ale and numerous folk medicine practices.