The different types of fronds are.
Maidenhair fern.
Sword fern.
Ostrich Fern.
Bird's-nest fern.
Australian tree fern.
Japanese painted fern.
Lady fern.
Phlebodium aureum.
Royal fern.
Asparagus fern.
Christmas fern.
Himalayan maidenhair fern.
Athyrium filix-femina.
Cinnamon fern.
Dryopteris erythrosora.
Hart's tongue fern.
Cyrtomium falcatum.
Sensitive fern.
Staghorn fern.
Autumn Fern.
Brilliantelse' maidenhair fern (adiantum raddianum 'brilliantelse').
Cinnamon fern (osmundastrum cinnamomeum).
Deer fern.
Interrupted Fern.
The two types of fronds are fertile fronds and sterile fronds.
Fertile fronds are the specialized fronds which bear sporangia which is spore producing structures and are involved in reproduction.
The sterile fronds are the typical leafy fronds that are responsible for vegetative growth and photosynthesis.
Immature fronds are called fiddleheads.
After the new fronds emerge which is often in the spring they then unroll and are called fiddleheads.
Fiddleheads are the edible young fern fronds also known as crosiers that rise from the plant every year in the spring.
If allowed to mature, the green disks or immature fronds will gradually unfurl themselves into the broadly splayed fronds of a typical fern.
Due to their short harvesting season, fresh fiddleheads are a rarity in North America and are therefore usually quite expensive and are considered a delicacy.
The fiddlehead fronds have been and still is an important food and medicine for Asians, Native Americans and many other people all throughout the world.
Some other parts of the ferns or fronds are also edible like the rhizome which are also edible and the mature fronds can also be used many different ways.
Fiddleheads are a seasonal vegetable which can be cooked and eaten.
The fiddleheads that are edible are the Ostrich Fern, Cinnamon Fern and Lady Fern.
Fiddleheads tend to taste like asparagus or broccoli, spinach or green beans.
You can cook the fiddleheads by boiling them in water and then discarding the water.