Winter Ferns 2024-2025

Sensitive Fern

This is what I would call the "dead of winter". Mainly because it is so hard to find any ferns that are not buried under the snow and ice. I am glad for the snow to replenish the soil and protect the plants from the very cold weather, but it makes for very boring hikes with very few ferns (or understory plants) to stop and look at. We are in the dead fern season, where about the only ferns I have seen lately are the very tops of the Sensitive and Ostrich fern fertile fronds poking through the snow!

Most of you know Sensitive Fern (Onoclea sensibilis) since it is one of our most common ferns, usually found in wetlands but sometimes also in moist or seepy areas. The rather simple sterile green fronds usually grow in dense patches with a fibrous rhizome mat just below the surface. The fertile fronds, such as pictured here, come out later in the season and persist through the winter. The pretty dark brown or black bead-like structures on the fertile frond are sori enveloped in a protective cover created by the pinnules. The spores are released from these covers in late winter and early spring. I have been seeing some of these fertile fronds with the "beads" gone.

It is easy to tell the difference between the fertile fronds of the Sensitive Fern and the Ostrich Fern, even at a distance. The Sensitive Fern has these bead-like structures, while the fertile fronds of the Ostrich Fern look like feathers. I will highlight them in the next news article.

Posted: to PV Fern News on Sun, Feb 23, 2025
Updated: Mon, Feb 24, 2025