Flora and fauna of the Athens County area, and occasionally habitats outside Ohio. Subject matter will consist of both interpretive material and taxonomic issues in plant and animal identification.
Wednesday, November 10, 2010
A Few Ferns
Ferns have been around for 300 million years, and were the dominant plants of the Carboniferous period. Ferns are non-flowering plants related to Ground Pines (Club Mosses) and the Horsetails.
Some types, such as this commercially available Boston Fern, have been used for centuries both in and around the house for ornamental plantings.
Ferns radiate out in many directions with multiple stems known as Stipes. The stem and leaflets together are known as a Frond. The leaflets themselves are called Pinnae.
They reproduce with spores, housed together in Sporangia or Sori. Some occur on separate stalks, others on the back of the pinnae or pinnule.
In the spring, many species are still curled in this shape known as "fiddleheads". Open ferns should not be consumed, but at this stage they are still edible. Since there are nearly 12,000 species worldwide, I hope to post another series come spring on types such as bracken, ostrich, polypody, cliffbrakes, and more.
This delicate species is one of the easiest to recognize in our forest understories, the Maidenhair Fern, Adiantum pedatum. Look for fronds spreading in a circular pattern. Up close, the leaf edges curl back and cover the spores.
Sensitive Fern, Onoclea sensibilis, is what I refer to as one of the "winged" ferns. The central stalk, or rachis, is flattened. Don't look on the back of the pinnae for sori, as this species produces a separate stalk of fertile leaves that turn brown and persist through winter. This is a species of wet soils.
Notice how the last pair of leaflets point downward, away from the rest of the fern. This tells me I'm looking at the Broad Beech Fern, Phegopteris hexagonoptera.
Like sensitive fern, this species has a winged center. The wings extend down to the last two pairs of leaflets on the Broad Beech. The similar looking Long Beech Fern, P. connectilis lacks these wings at this same location.
Royal Fern, Osmunda regalis. Royal fern leaflets appear separated or further apart than that of other ferns. This is because they are entire, containing no lobes or subdivisions. The spores are on fertile stalks growing apart from the other pinnae. Royal Ferns are found in wetlands.
When I first look at this plant, I notice the wide spacing of the alternate arranged leaflets. This is the Lady Fern, Athyrium filix-femina.
The lady is blushing. Look for the rich red stems as an identification character on Lady Fern.
Lady Fern has large elongate sori on the back of the leaflets.
Cinnamon Fern, Osmunda (Osmundastrum) cinnamomea, is a tall plant found in areas of moist to swampy soils. The fertile fronds are separate and rusty orange in color. Fibers of the plant are used as a mulch for flower pots.
If the fertile fronds are absent, run your fingers down the base of the plant. It is covered with a mass of furry orange hair.
Look at the area where the leaflet meets the rachis or stem. There will be a small cluster of orange fuzz, or 'hair in the armpits'.
Interrupted Fern, Osmunda claytoniana. Named after the fact that midway up the frond, the leaflets are interrupted by the brown fertile spore section. Sometimes an empty space can be seen when the spores have all dropped. Otherwise it is similar in appearance to Cinnamon Fern. The tips of each lobe or pinnule are more pointed on cinnamon, and blunted or rounder on interrupted.
Speaking of ferns with blunt or round tips, this is what I see when looking at the Marginal Wood Fern. The tips appear to be shaved or cut off.
To make sure you're looking at Dryopteris marginalis, turn over the leaflets and notice the little round sori on the edge or 'margins' of each pinnule. The white are early season sori, the brown are mature.
This is Spinulose Wood Fern, Dryopteris carthusiana (spinulosa). I have heard it described as the "ferniest of all the ferns".
I think that description comes from the look of the highly divided leaflets and the bristly tips of each pinnule.
When looking at the undersides, I see round sori more centrally located, and in pairs.
Not much of a picture really, but for identification, it serves a purpose. This is the New York Fern, Thelypteris noveboracensis. What's clearly visible is the way the fern narrows or tapers at BOTH ends.
Found in moist woodlands, it does best where the sun penetrates the canopy. It is quite acid tolerant.
Deparia acrostichoides. Silvery Spleenwort, or Silvery Glade forms large clumps in woodlands. Viewing from a distance, I'm not surprised if someone says "looks just like all the other ferns". Frankly I have to agree.
Of course upon a closer look, the leaflets are completely covered by elongated sori. This is a shot late in the season. Early on the sori are bright white, giving the plant a silvery sheen throughout.
Ebony Spleenwort, Asplenium platyneuron, is found in rocky soils. The base of the leaflets are swollen, somewhat like that of Christmas Fern.
The fertile fronds grow erect and the stems range from a deep reddish-purple to black. The young sori are arranged in V's, and upon maturity appear mashed together in the center of the pinnule.
A small fern with tightly compacted, rounded leaflets, is evidence of Blunt-lobed Woodsia, Woodsia obtusa. The margins are heavily serrated. These plants were only about 8 inches, but will grow twice that length.
It prefers alkaline or limestone soils and rocky outcrops. It's often called Cliff-fern.
Sometimes looking more like a grass than a fern, the Walking Fern, Asplenium rhizophyllum, is a rather uncommon species. Look for it on moss covered rocks.
Other than spores, Walking Fern can spread by tip-rooting with the long tapering portions of the frond, thereby "walking" from one spot to another. Dense colonies may develop from this habit.
Also unusual looking are the grape ferns. This is Cut-leaved Grape Fern, Botrychium dissectum. Leaves radiate out basally with the fertile frond projecting upward through the center. Plants are highly variable, ranging from weakly to heavily serrate, and shallow to deeply lobed. Plants appear triangular, or at least growing in three directions.
Floating on the surface of ponds and lakes is the Water Fern, Salvinia minima. Introduced from South America, it has spread throughout the gulf states, and competes with native aquatic plants. The leaves are small and oval and covered with erect hairs. The leaves lie flat on the water surface. With age, the leaves may fold toward the middle, giving it a miniature Venus Fly Trap look. It spreads through rhizomes dangling beneath the leaves.
Displaying four leaves, the Water Clover, Marsilea quadrifolia, is another invasive aquatic fern. Being from Europe, it can withstand our winters. It has become established in the New England states, and occurs occasionally in the midwest.
A perfect match! The similarities are just striking, no explanation is even necessary now is it. Santa and his reindeers silhouette must mean Christmas Fern, Polystichum acrostichoides. The thick leathery fronds are evergreen. It is by far the most common fern in our area. More ferns can be found here