The ferns are primitive plants dating back to the dinosaur era, when they grew to the size of trees.
Reproduction
Ferns, mosses, lichens, and fungi all reproduce by means of spores, which function like seeds with some important differences: 1) fertilization takes place after departure of the spore from the parent plant; 2) the spore develops into a separate plant-like structure with male and female parts that accomplish fertilization; 3) spore-bearing plants require water for fertilization, rather than wind or insects. (See Seeds versus Spores for more details.)
Characteristics
When identifying, it is helpful to know that most ferns have compound leaves, that is, multiple leaflets lining a longish stem. Once-compound leaves are coarser in appearance than twice-compound (or twice-cut) leaves, whose leaflets also have stems with leaflets of their own, creating the familiar “fernlike” feathery look. A few species go as far as thrice-compound leaves.
Many ferns bear their spore cases (also known as sporangia, sori, or fruit-dots) on the undersides of some of the leaflets—turn over the leaves and look for small dots, often brown. Other species have separate stems devoted to holding spore cases. These structures have fertile leaves that usually look like miniature versions of the larger plant but later turn brown and curly.
Identification of many of the twice-compound species requires examining placement of spore cases; comparison of sizes, shapes, veining patterns, and numbers of leaflets; and other meticulous evaluations, which obsessive botanists usually enjoy. A Field Guide to the Ferns, from the Peterson's Field Guide Series, is a classic identification handbook, worth buying just for the exquisitely drawn pictures.
Below are a few fern species that are easy to spot.
- Christmas Fern
A common once-compound woodland variety. The leaflets are shaped like Christmas stockings, with a little protrusion at the base of each leaflet. The name, however, comes from the fact that this fern is still green around Christmas time.
- Sensitive Fern
The name comes from the tendency of the foliage to die back with the first frost, leaving behind the erect, dark brown fertile spikes with hard, beadlike leaflets. (The other common name of the species is Bead Fern.) The green plant is once-compound, the leaflets having wavy edges and netted veins. It tends to be found in damp areas, in full sun or shade.
- Maidenhair Fern
This endangered species is found occasionally in the woods. Elegant twice-compound fronds are mounted on a stem that splits and spirals in two directions, with the delicate leaves lining the outer edges of the circles.
- Interrupted Fern
A handsome plant that can grow up to waist-high and is found on roadsides, on forest margins, and in gardens. Its twice-compound leaves have the typically feathery look but are interrupted along the central part of the stem by smaller fertile leaflets that later turn brown and coiled, eventually falling off the plant and leaving a space along the stem.
Violet Snow - Violet Snow is a naturalist, herbalist, photographer, journalist, and outdoor educator. She has taught classes for the Appalachian ...
