The specialized leaves of a fern are called fronds.
The term “frond” is used in several different ways. Most commonly, when someone talks about a frond, he or she means a pinnately compound leaf or leaf-like structure on a plant, such as the fronds of a palm tree. This usage reflects the Latin root of the world, as “frond” is derived from the word for “leaf” or “foliage.” The world of fronds is actually quite complicated, as a number of very different structures on plants and other organisms are also called fronds.
Classically, a frond has a feathery appearance, with a long shaft in the middle of the structure and lacy extensions which protrude from the shaft. In some fronds, each protrusion is entirely separate, while in others, the protrusions may join together before the reach the shaft, creating which is known as a “palmate” appearance which looks like the palm of a hand.
Originally, this term was used to refer to the leaf-like structures of a fern. The fronds of a fern are distinct from ordinary plant leaves because they bear spores, since ferns do not flower. A fern frond arises from the rhizome of the plant, developing initially as a tightly coiled fiddlehead which slowly unfurls. Some ferns also experience frond dimorphism, in which the male and female fronds look very different.
This term is also sometimes used to refer to the thallus of a fungus. Fungi do not have leaves, but some develop masses of tissue which superficially resemble leaves. When a fungus has a thallus which looks similar to a fern, the thallus may be called a “frond.” Some fungi develop very lacy, elegant structures which do indeed look like fern fronds, even if they are not true fronds, and on occasion fungi may even be mistaken for ferns by casual viewers.
Plants with foliage which resembles that of a fern may also be said to have fronds. Many ornamental plants have frond-like leaves, and the fronds of some plants like palms also have cultural significance. Fronds have been used to roof structures in some societies, and as fans, ornaments, and even plates in some cases. They also have a history of use in religious ceremonies, especially in Christianity and Judaism. Gardeners may find the appearance of a plant with large fronds appealing, and utilize it as a showpiece in a garden, especially in the tropics, where frond-like leaves are very common, and some plants grow extremely large.