Explore » Our Campus » Nature Center » Ferns » Glossary of Terms

Glossary of Terms


Found in the early spring when new fronds are growing. The curled and growing blade resembles the end of a fiddle.

Frond (Leaf, Blade)

Flat, green, photosynthetic part of the fern plant. Supported by a stipe (stem). May be fertile (with sporangia) or sterile (without sporangia).

Pinnae (singular Pinna)

First division or cut of a blade.


Second division or cut of a blade. First cut of a pinna.


Third division of cut of a blade. First cut of a pinnule.

Sori (singular Sorus)

Collection of many sporangia. Referred to as "fruit dots" when found on the underside of blades.

Stipe (stem)

Supports the blade of the frond, below the rachis.


Microscopic, usually single celled, reproductive propagule. Analogous to the seed of a flowering plant.

Sporangia (singular Sporangium)

Very small, ball-like structures within which spores are produced.

Rachis (axis)

Part of stem supporting the leaflets or divisions of the blade; above the stem.

Once-Cut Frond

Blade divided into just pinnae.

Twice-Cut Frond

Blade divided into pinnae and pinnules.

Thrice-Cut Frond

Blade divided into pinnae, pinnules, and pinnulettes.

← Return to Ferns