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350 million years and counting: The unusual life cycle and history of ferns

  • Anne Lombard turns over a Braun's holly fern to reveal the sori, or spores, of this fertile specimen. <br/>KEVIN GUTTING
  • A crested wood fern in the Northampton garden of Anne Lombard. <br/>KEVIN GUTTING
  • An oak fern in the Northampton garden of Anne Lombard. <br/>KEVIN GUTTING
  • Ferns make up a large portion of Anne Lombard's back yard garden. <br/>KEVIN GUTTING
  • A long beech fern in the Northampton garden of Anne Lombard. <br/>KEVIN GUTTING
  • The underside of a Braun's holly fern is covered with sori, or spores, on this fertile specimen. The appearance and placement of the sori can help identify a fern.<br/>KEVIN GUTTING
  • The underside of a narrow-leafed glade fern in the Northampton garden of Anne Lombard. <br/>KEVIN GUTTING
  • The stem of a marginal wood fern in the Northampton garden of Anne Lombard. <br/>KEVIN GUTTING
  • Anne Lombard holds maidenhair fern in her Northampton garden. <br/>KEVIN GUTTING
  • Anne Lombard of Northampton walks through her back yard garden thick with ferns. <br/>KEVIN GUTTING
  • Anne Lombard holds maidenhair fern in her Northampton garden. <br/>KEVIN GUTTING

The surfeit of water in June caused some plants to rot, much to the dismay of local gardeners. Before the current heat wave, however, ferns were thriving.

“They are very happy this summer,” Anne Lombard of Northampton, a local fern enthusiast, reported in early July.

Lombard has a small fern garden in the backyard of her downtown Northampton home and she also leads field walks about ferns at Arcadia Wildlife Sanctuary in Easthampton. I learned a great deal about ferns on a walk with Lombard in June and interviewed her in her own garden this month.

Ferns love shade as well as moisture and are a natural plant for shade gardens. Lombard’s fern garden is squeezed between her house and her garage that was a “big brown muddy area” when she moved there 10 years ago. The soil was quite impacted so she amended it with compost from Smith Vocational and Agricultural High School in Northampton. Now she never has to fertilize and only waters during real dry spells like the recent heat wave.

Why specialize in ferns?

“It’s a manageable group of plants to study,” she explained. There are just 50 to 60 fern species native to New England although there are 12,000 throughout the world. Their incredible variety and range is one reason people study them. Ferns are found from the tropics to the polar regions. Once on a trip to Iceland, Lombard recognized two of her favorites: oak fern and fragile fern far from New England. In the south she learned about resurrection fern (Pleopeltis polypodioides), a species that grows in trees along the branches. “It shrinks in dry weather and comes alive when it rains,” she said. “It’s good to have a special interest when you travel,” she added.

A retired high school biology teacher, Lombard said ruefully that while she taught the structure and life cycle of plants in the classroom, she wasn’t able to take her students on field trips to learn natural history.

Now she volunteers at Arcadia, leading field walks for adults and going to local schools to help children get outside to observe nature first-hand.

When she first became interested in ferns, she went to Garden in the Woods in Framingham, the home of the New England Wild Flower Society, to take field walks and workshops on ferns. She also took a fern propagation workshop at Nasami Farm in Whately, the nursery for the Wild Flower Society.

Ferns have an unusual life cycle, she explained during the Arcadia walk.

Instead of producing seeds they produce spores, usually on the back of the fronds or on separate spore stalks. In June, the spore cases are pale green, barely distinguishable on the fronds. By August they are brown and ready to release their spores.

“There can be 70 million spores on a single fern,” she said. “The spores are tiny, very powdery.” When released in late summer or early fall, they land in the soil and some — in ideal conditions — grow into the second stage of ferns, the prothallus. This is a tiny structure, round in shape, so tiny, Lombard said, she has never found one in the wild. Yet, unseen by humans, it develops male and female organs and, helped by rain, the sperm swims across the prothallus to the egg and fertilized eggs become the ferns we recognize.

Among the colorful blooms of wildflowers, many people ignore the beauty of ferns. But they vary in size, frond shape and texture, color and habitat. Some are quite common while others require such specific conditions that they are rare in nature and in gardens.

Starting a fern garden

If you want to get started with a fern garden, Lombard recommends getting a Christmas fern (Polystichum acrostichoides).

“It’s green all winter and very hardy. That would be an excellent choice,” she said.

Another common, readily available fern is the ostrich fern (Matteuccia struthiopteris), the one from which edible fiddleheads are harvested.

“It needs wettish conditions,” she warned, “and it does spread. A stolon grows underground and may pop up where you don’t want it.”

On the other hand, “any of the wood ferns” (Dryopteris) would be good for a beginner.

“They do not spread. They grow like a bouquet flower cluster.”

Wood ferns, Christmas ferns and many others are “clumping” types that tend to stay within bounds.

“I would discourage new gardeners from planting hay-scented ferns or sensitive ferns,” Lombard said. They grow singly rather than in a clump. Hay-scented ferns are Dennstaedtia and sensitive ferns are Onoclea. “The hay-scented grows like an army of soldiers marching across a field,” she commented on the field walk.

Identifying ferns can be a challenge, but after a session with Lombard, some traits become obvious. All wood ferns, for instance, have brown scales on their stipe (stem) which Lombard notes looks “scruffy.” Some ferns have distinctive spore cases. The lady fern’s (Athyrium) spore cases look like commas while the maidenhair (Adiantum) has an indusium, a tissue that folds over the edge to protect the spore case. The marginal fern (Dryopteris marginalis) is so-called because its spore cases are arrayed along the edge or margins of the frond instead of throughout the back of the frond.

Ferns can also be identified by their habitat. Maidenhairs and purple-stemmed cliff brake (Pellaea atropurpurea) prefer limey, alkaline soil. Lombard placed large bricks next to her purple-stemmed cliff brake and makes sure to spray the brick every time she waters her garden, to help the lime leech into the soil.

Oak ferns are one of her favorites. It has a distinctive black stem — as does the maidenhair. One reason Lombard is fond of the oak fern (Gymnocarpium) is that there are carpets of it near a family cabin in New Hampshire. Another favorite is Braun’s Holly Fern (Polystichum braunii), which is semi-evergreen in the same genus as the Christmas fern. It is more common in northern New England and in Canada but Lombard has a nice specimen in her garden.

Lombard has about 20 fern species in her small garden. When she first planted ferns, friends gave her specimens from their gardens. She has an ostrich fern from Hadley and a wood fern from Cummington. Over the years she has purchased many from Nasami Farm and from a vendor at the Northampton Farmers Market. She said you should never dig ferns or any other wildflower from property other than your own and should inquire when purchasing whether the plant was propagated in a nursery or wild-dug.

A little pathway wends through Lombard’s fern garden where there are also several wildflower species. Many of them simply “appeared” probably growing from seeds in the soil of ferns she brought in. In spring she has May apples and trilliums as well as a Jack-in-the-pulpit which was a gift from her sister. In bloom in July were round-leaf aster with white flowers and a tall meadow rue. Offering contrast to the lacy texture of ferns were many European ginger plants with thick, shiny, round leaves. A few unusual rocks, a conch shell and even a tiny gnome are accents along the path.

Some ferns simply dislike cultivation. Lombard pointed out a polypody fern “that is not happy here.” She has seen Ebony spleenwort (Asplenium platyneuron) growing nearby on a masonry bridge but it wouldn’t thrive in her garden either. And, she said, her garden is too small to accommodate cinnamon fern (Osmunda cinnamomea) or royal fern (Osmunda regalis), both of which grow very large.

Lombard says she loves to go ferning, which, she said, is akin to birding, taking field walks at nature centers throughout the area.

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