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Fern Talk - Common terms used in fern nomenclature

Common Fern Terms

The Frond Parts

Below: Parts of a fern.

Fern Key

Below: Pinna on blade that has secondary and tertiary divisions.

Wood fern pinna

Below: The unusual structure of Bracken Fern where the blade divides into three very large pinnae.

brackenfern pinnae
Pinnatifid blade division
Pinnate (or 1-pinnate) blade division
1-pinnate pinnatifid
Pinnate-pinnatifid blade division. Pinnules not cut through
Bi-pinnate-pinnatifid or (2-pinnate-pinnatifid) blade division. Some pinnules cut through.
Tri-pinnate-pinnatifid (or 3-pinnate-pinnatifid) blade division. Pinnules on pinna cut through and some lobes on pinnules cut through.
Scales on stipe
Stipe with brown "scales"

Reproductive terms and locations of sori and sporangia

Sori on frond
Exposed sori on pinnules of frond of Lady Fern
Indusia over the sori on pinnule of Goldie's Fern
Sporangia on fertile frond of Sensitive Fern.
False Indusium
False indusia on pinnule margin of Maidenhair Fern