FINDING FERNS

By RUTH SMITH

For the Monitor

Published: 08-05-2020 10:38 AM

At this time of year many people, not just gardeners, think about plants. Gardens are lush with flowers and ripening vegetables. Meadows, wetlands and forests are rich with the colors and textures of hundreds of species of flora. But one group of plants is often overlooked – the ferns.

Ferns are ancient plants. Fossil records show that they first appeared about 360 million years ago. If that isn’t reason enough to appreciate them, I don’t know what is. But there is more to like about ferns.

They have a fascinating life history. Instead of producing flowers or seeds like other vascular plants, they make spores, sometimes millions of them. One scientist estimated that a single leaf from a wood fern produced 7 million spores! The spores come in little cases called sori. In some species they are found on the underside of the leaf or frond, while in other species they grow on a separate fertile frond. The pattern of the sori on the leaves or the shape and color of the fertile frond are often used as distinguishing identification features.

When the spores are ripe, they are catapulted into the wind and dispersed. The chances of a spore landing in a place with optimal conditions for growth are rare, hence the need for so many. However, if it does find the conditions it needs, the spore doesn’t sprout into a fern. Rather it develops into an intermediate generation, a tiny plant called a gametophyte. Here the eggs and sperm are produced and fertilized to develop into the generation we know as the fern.

At first glance ferns may all look similar, but there is a great deal of diversity, starting with their habitat. For example, hay scented ferns grow in open fields, royal ferns are found near stream banks. Some grow in tight clumps, others spread out in large patches. Getting to know a few common species is actually quite easy.

To begin, it’s important to know some terminology. The frilly, sometimes drooping part we usually refer to as the fern is the leaf, or frond. Its stem is called the stipe or stalk. The little fingers that branch off the stipe are called leaflets. This is where it starts getting tricky. In some ferns, the leaflets are divided multiple times. If each leaflet has a complete margin, it is described as once-cut. If the leaflets are divided a second time, it is twice-cut. If there is an additional division, the fern is described as thrice-cut. Thrice-cut leaflets produce a very lacey appearance, whereas the once-cut ferns are much coarser and tough looking.

The first fern that I learned to identify was our most common species, the bracken fern. Look for a frond that is about three feet tall and branched, with three leaflets emerging from a central stem. It comes up early and produces rather tough dark green leaves all season. Though it can grow in a variety of habitats including full sun, woods or old pastures, its presence usually indicates poor soil.

Another favorite is the interrupted fern, given its name because the brown, fertile leaflets appear part way up the stem, interrupting the pattern of the other green leaflets. It is tall (3 to 4 feet) with fairly coarse leaves and can be found along roadsides or the edges of woods. It appears early in the spring and turns brilliant yellow in the fall. The cinnamon fern is a similar species where spores grow on a separate frond.

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The sensitive fern is not dainty, but gets that name because it dies back with the first frost. This is in contrast to the Christmas fern which grows low to the ground and remains green at Christmas and throughout the winter.

If you happen to find a large boulder, examine it for the presence of the polypody fern. This species is also evergreen and quite diminutive as it sprawls across the surface of rocks. It is perhaps my favorite fern because it clings to rocks with a tenacity that defies its size.

Without much effort, I found eight or nine species of ferns on a short walk near my house. Why not explore your favorite natural area with new eyes and check out the living fossils that are growing near you?

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