Category Archives: Plants

Wetland Ferns Webinar

February is one of my favorite months. Some may dislike “dreary February” but I am biased; it’s my birthday month. As a special treat, I participated in an afternoon “Swamp Seminar” to learn how to identify northeastern wetland ferns. The webinar is part of an online training series offered by Swamp School. After the training, I earned a certificate.  Since I’ve written about ferns a few times for this blog, I thought I better brush up on fern morphology, before I made a fern faux pas. And as it happens, I was wrong about one plant: sweet fern (Comptonia peregrina) is a member of the heath family, not a true fern.

The “Swamp Seminar” on wetland ferns started with the parts of a fern. Prior to this class, I knew to refer to the frond, which is the whole fern leaf, and I understood that rhizomes are the roots, but the rest of a fern’s morphology was new information. It was fascinating to learn that a fern might be identified based on whether it is once, twice or thrice pinnate–meaning, the number of cuts on the pinna, or leaflet. Lady Fern, a common fern that grows throughout the northeast, is three-times pinnate with a rough-edged leaflet, making it look lacy. Several ferns have similarly feminine names like Venus Hair Fern (Adiantum capillus‐veneris) and Northern Maiden-Hair Fern (Adiantum pedatum), or Maiden-Hair Spleenwort (Asplenium trichomanes), which grows near waterfalls and is said to be “good for the spleen.”

For wetland professionals, the training addressed whether each fern is an Obligate Wetland species, meaning that it always occurs in a wetland, also known as a hydrophyte (loves water); a Facultative Wetland species, which means that the fern usually shows up in a wetland, but can also be found in upland areas; or, thirdly, it may be a Facultative species, commonly occurring in both wetland and upland areas. Ferns that fit this last category–facultative, are still important to know because they may help someone identify the edge of a wetland.

Identifying wetland plants is fairly complex. See this USDA page on wetland indicator information, for a more specific explanation. Last fall, the National Wetland Plant List was updated and published by the Army Corps of Engineers. ASWM offered a training session on how to use the NWP List website (see this recorded presentation).  Several publications are also available that aid in using this plant list, including A Field Guide to the National Wetland Plant List: Wetland Ratings for Plants of the United States by Steve Chadde, 2012.

Among the many types of ferns covered in the Swamp Seminar, participants learned how to identify Sensitive fern (Onoclea sensibilis), Fragile fern (Cystopteris fragilis) and Interrupted fern (Osmunda claytoniana), which has a distinctive shape. The Swamp School webinar included access to an online tool kit, which allows participants to reference handouts. The website and webinar training are well-organized and condensed to relay a great deal of knowledge. It’s suitable for intermediate and advanced levels—and ideal for wetlandkeepers. Swamp School also offers classes on wetland delineation–in both classroom, field and webinar formats with live, interactive training.  For more information, visit

Update: Hydric Soil Indicators Webinar March 20, 2013. For more information,

Destiny of Waters

Is it a lake or a pond or a wetland?

Recently someone asked me about the body of water beyond my backyard—if it was a lake or a pond and what’s the difference? My first answer was that it is a pond by name. A pond or lake may be named as such the way “street,” “lane,” or “road” are often interchangeable. Secondly, a lake and a pond have differences at the ecological level—in terms of aquatic life, and in terms of limnology.  I also explained that the differences had to do with acreage and depth of the water body. Sometimes a “pond” can be bigger and deeper by comparison to a nearby lake, as in the case of Long Pond (113’ deep) and Echo Lake (66’ deep) in Acadia National Park. In that case, Echo Lake is technically considered a “great pond” under Maine state law because it’s a natural pond greater than 10 acres.  But usually lakes are bigger and deeper than ponds. State definitions generally include both lakes and natural ponds as “waters of the state.” Under the Cowardin classification system, ponds are wetlands.

What I did not explain to my friend very well was the natural gradation of lakes into ponds into wetlands, and their evolution as waters.  What made sense to me as an ecologist, that one type would naturally grade into another water type, was harder to explain. What’s even harder to illustrate is the concept of an ecotone—the transitional area between two ecological communities adjacent to one another. As usual, I thought of movies.

The phenomenon of distinct communities existing side by side can be observed in film.  For example, the liminal space between cultures—a cultural transition area—can be viewed as bordercrossings, illustrated effectively in films like “Night on Earth” (1991). Jim Jarmusch’s film took place entirely in taxi cabs in five different time zones throughout the world. The concept is that no matter where you go, at one point in time, there are eerily similar transactions and interactions taking place in taxi cabs—a kind of cultural habitat, if you will—for humans migrating from one place to another. Some water bodies, like taxi cabs, are mobile; some are stationary, like an ‘off-duty’ cab.  And that’s where the changes from lake to pond to wetland, or the line between adjacent ecological communities, can get a little fuzzy to someone standing on the curb, er, the edge of the water.

Over what period of time do lakes become ponds? How long does it take for ponds to become wetlands? For wetlands to become meadows? The short answer is several thousand years, if nothing has interrupted (or accelerated) the natural evolution of these waters. This is called succession. Biology students learning about wetland succession in a classroom can experiment with an aquarium—starting with a mini pond or wetland habitat. For a biology teaching guide written by BioMedia (Russell) that outlines the key ingredients to such an experiment for a year-long study,click here. Limnologists say, “lakes are destined to die,” whereas ponds are the “death of a lake” and the “birth of a marsh.” For an explanation on pond succession, click here.

So how does a pond become a wetland? The first stage, called the ‘pioneer’ stage of wetland succession, starts with the pond without plant life at the bottom. Plankton, which inhabit the pond, and carry miniscule plant and animal life, arrive on the winds or wings of insects.  Over time, plankton die on the pond bottom and create a mucky layer, which is rich enough for water emergent plants to grow, such as water lilies, ancient wetland plants. As water lilies form a blanket over the surface of the water, they cut off the sunlight to the bottom, killing off the submergent plants. These processes can take a variety of timeframes from a matter of years to a matter of millennia. Trees, shrubs and grasses move into the space that was once the pond and a wetland takes shape. This is a dynamic process with many variables. Some wetland ecologists have argued against the idea of wetland succession because of these variables.

Succession is not a sure thing. It does not occur with all lakes in the U.S.. (For instance, there is no scientific concern that the Great Lakes will eventually turn into ponds, or meadows.) There are many factors that can interrupt a “natural” succession process such as a changing climate, soils, drainage, land development, introduction of invasive plants or other aquatic species, phosphorus run-off (causing dissolved oxygen) or other factors.

In addition to the possible succession pattern of pond to wetland, some wetlands can be turned into ponds. In the U.S. Fish & Wildlife Service’s Status & Trends of Wetlands in the Conterminous United States 2004-2009, ponds are recognized as a type of freshwater wetland. The report indicates a net increase of 207,200 acres of ponds between 2004-2009, an increase of 3.2% in ponds nationally (FWS).  The trouble with ponds, for example, farm ponds, being created while another type of freshwater wetland is lost, is that there is a difference between constructed ponds and wetlands—including natural ponds, in terms of their ecological functions. According to the Status & Trends Report, the majority of ponds in the U.S. are constructed farm ponds. Only 31% of the ponds in the lower 48 states are natural.

Mankind has a dramatic impact on natural landscapes frequently disrupting succession. This means it’s an uncertain destiny for our lakes, ponds, streams, rivers and wetlands. For those working to protect wetlands, and to harness the power of wetlands to sequester carbon and provide unique and solvent ways to fight climate change’s impact on our planet, this is cause for concern. Save wetlands, save ourselves.

Helpful Resources:

Massachusetts Lake and Pond Guide

Wisconsin’s Natural Communities

Michigan DNR: Succession – Changing Land, Changing Wildlife

Wetland Ecosystems by William J. Mitsch, James G. Gosselink et. al. (2009)

Wetland Ecology: Principles and Conservation, 2nd Edition by Paul Keddy, (2010)

ASWM’s Wetland Science web resources

Other recent blogs on wetland succession:

Conservation Maven: Study finds post-restoration wetland succession highly variable

Ian Lunt’s Ecological Research Site: There’s a wetland in my grassland

Constantine Alexander’s blog: Artificial wetlands can provide benefits over the long haul(on Bill Mitsch’s work on wetland creation and succession)

Water Lilies & Floating Ferns: Dip into the Deep Past of Ancient Aquatic Plants

“The rapid development, as far as we can judge,
of all the higher plants within recent geological time
is an abominable mystery.” ~Darwin

Last night I enjoyed Woody Allen’s film, “Midnight in Paris,” a surrealistic journey into the past. Cinematic stills of Paris open a dreamy storyline, in which the protagonist, a writer searching for his voice among his literary and artistic idols, finds inspiration strolling through the city at midnight. In one scene, he stands before Monet’s famous paintings of water lilies. Gazing at those water lilies transports him back in time.

Water lilies are decedents of the most archaic of the flowering aquatic plant world. Fossils of earlier versions of these aquatic plants are evidence of their great age. By the mid-Cretaceous period, angiosperms dominated the planet. Water lilies were among the earliest fossil flowers found.  Basal angiosperms including water lilies such as Nymphaea, Brasenia, Nuphar remind us of a deep evolutionary past of the flowering aquatic plants. In 1904, Ohio State University botanist J.H. Schaffner asserted that water lilies are the very “stock” from which all flowering plants stem. This belief wasn’t readily embraced by other scientists of his time but his observations about Nymphaea were later confirmed.

Those who study aquatic plants even today will admit they are difficult subjects with converging and evolving morphology. “Precise clues to Darwin’s ‘abominable mystery,’ the origin of flowering plants, have eluded systematists for more than a century,” according to authors of a study on the “Molecular evolutionary history of ancient aquatic angiosperms.” (Les, Garvin, 1991) There are lots of unanswered mysteries surrounding water lilies in particular, for instance, whether they are monocots or dicots. There are differing viewpoints among scientists. Water lilies are simply an unusual group of plants. The origin of angiosperms (flowering plants) is at the heart of Darwin’s “abominable mystery.” Darwin, along with many scientists after him, have sought to answer questions about the rise of flower-frequenting insects and the origins of certain plants on isolated islands.

Water quality monitors can look for certain aquatic plants as ecological indicators. A quick Google search for “water quality” will reveal that water lilies are often used as symbols for ‘good water quality’ if only because they are hardy aquatic plants and thrive in freshwater lands, ponds and wetlands. However, they are native to the eastern U.S. and were introduced to the western states in the early 1800s. In some areas, water lilies have been regarded as an invasive (or) non-native species. For example, here is a King County, WA fact sheet on non-native water lilies and management of them as an invasive species: and Non-native freshwater plants on the Washington State Dept of Ecology website (a fact sheet on Nymphaea odorata including habits, pollination strategy, uses by Native Americans, status as introduced plant.)

Ferns are also considered “dinosaurs” of the plant world. Aquatic floating ferns, such asAzolla, a tiny water fern, also called mosquito fern; Marsilea, also called water clover;and Salvinia, a water fern native to tropical America, are unusual since most types of ferns are terrestrial, not aquatic. Floating ferns are heterosporous, which makes them the most advanced type of fern. Just think—there are around 9000 species of living ferns and fewer than 1% produce spores (similar to seeds). This is true of the water ferns with the genus of Azolla, Marsilea and Salvinia.

Mosquito ferns can be aggressive invasives—quickly covering the surface of a quiet pond, providing habitat for macroinvertebrates, a food source for reptiles and amphibians. But if the little fern, which can be green or reddish in color, covers the surface of the whole pond, it can deplete the oxygen and lead to fish kills. Surprisingly, because of its aggressiveness, mats of azolla can reduce the occurrence of harmful algae blooms and limit the growth of exotic aquatic plants, such as water hyacinth. For more about azolla water ferns, go to:

About ten species exist within the Salvinia genus. Related to the azolla water fern,Salvinia floating ferns have unique abaxial leaves (facing away from the plant) and creeping stems, but no true roots. Giant Salvinia is native to South America and an introduced, invasive species here in the U.S., including Louisiana lakes and Florida.

Water clover looks like four-leaf clover only it’s a floating fern in the Marsilea genus. It spreads by a thin hair-like underwater rhizome structure. Of all the floating ferns,Marsilea is the most species-rich with between 45-65 species. There are a number of great books available on aquatic plants, including Fern Ecology Ed. Klaus Mehltreter, (2010) and A Manual of Aquatic Plants by Norman Fassett (2006). For these and other wetland ecology books, visit the Wetland Bookshelf:

But what inquiring minds want to know…is the four-leafed water clover lucky? It’s become a popular plant to grow in garden pools (because it is so easy to manage) and even brought inside as a houseplant! At least one blogger calls it the “lucky charm” of the pond:

Fortune-telling with Wetland Plants

A long time ago, someone introduced me to Celtic divination with trees. The tree that stood for my birthday month was the ash. TheNuin, or ash tree, was considered the “Goddess tree,” and the wood was commonly used for Druid wands and the handle of a broomstick.
 A witch’s broomstick was made from ash to ‘protect the rider from drowning.’ The myth may have been derived from the tree’s tendency to live in wetlands. In Maine, for example, Black ash swamps are home to the showy lady slipper, and small enchanter’s nightshade, as well as mosses and liverworts that often carpet the floor of this forested wetland. It just so happens that swamps, along with other wetlands, have been places where fortune-tellers have sought plants for the purpose of divination, such as fig, sage and verbena.

Botanomancy is an ancient method of divination by means of the burning of leaves, herbs and tree branches. Usually vervain (Verbena officinalis), or any of a group of herbs or low woody plants with often showy heads or spikes of five-parted regular flowers, is used to predict fortunes. In addition brier, a plant with a thorny or prickly woody stem, such as any in the genus Rosa (roses), or Rubus (brambles), were used to predict omens. Omens are drawn from the smoke and ashes generated. This divination method was used for centuries by Babylonians, Greeks, Romans, Arabians, among many other civilizations. It is still used today by modern fortune-tellers. Fortune-tellers carve their questions on the branches prior to burning them. Alternatively, botanomancers write words on sage or fig leaves. Fortune-tellers expose the leaves to the wind and whatever leaves remain hold the answer. Historically botanomancers also observed the growth patterns of these plants; any odd behaviors or aspects of the plants would reveal information that could be used to predict events.

One of the plants used in botanomancy is the Swamp verbena, a.k.a. Blue vervain,(Verbena hastata), which can be found in degraded wetlands as well as high quality wetlands. It is common throughout the Midwest. It has pretty blue or violet flowers. The leaves are big enough to write words on, so this would be a good choice for a botanomancer.
 Now for those who love growing hybrid iris, don’t be fooled by the common name of the Tall Bearded Iris—Fortune Teller, which is neither a naturally occurring flower nor used in fortune-telling. It was cultivated in the 1980s.

Reading tea leaves, or tasseography, is another type of ancient divination. With roots in Asia, the Middle East and Ancient Greece, the tradition has been widely practiced throughout Europe (Scotland, Ireland) and Eastern European cultures. Because of the wide practice of tea reading, any kind of whole cut tea leaves may be used. The aromatic leaves of Bog Labrador tea plant (Rhododendron groenlandicum),which grows in bogs in northern climates, make an herbal tea. Please note: even though Bog Labrador tea is known for its medicinal properties, it does contain ledol, a poisonous substance that can cause cramps and paralysis! Always take care when making teas from unknown plants. In China, bulrush tea is a common beverage and Chinese tea is often used in tea readings.

After tasseographers drink tea, the wet dark tea leaves form shapes at the bottom of a cup, or the leaves can be tossed onto the saucer; then the shapes are interpreted. Tasseographers work with whole tea leaves. It is ill-advised to simply use the tea from a broken tea bag. The symbolism involved in reading tea leaves is based on a variety of theoretical foundations ranging from Plato to Carl Jung. There are numerous books available on how to interpret tea leaves. It’s a fun activity for a Halloween party or get-together. The basic instructions can be found here:

Weird and Wild Venus Fly-traps

I was about twelve years old when I first saw Little Shop of Horrors, (1986) with Rick Moranis and Steve Martin. I loved it. The remake of the 1960s film featured one of the most famous Venus flytraps—Audrey II (or Audrey Junior). The geeky florist Seymour cross-breeds a special plant using a butterwort and a Venus flytrap. It grows very large and likes the taste of blood—oh wait, it talks! It sings! It kills. Venus flytraps have appeared in cartoons and TV shows, such as Inspector Gadget, The Simpsons and The Addams Family. The lethal allure of the Venus flytrap made the real plant more popular off-screen.

Why so popular? Venus flytraps are a carnivorous plant, not unlike pitcher plants These plants don’t just eat insects; if a frog or mouse blunders into one, the plant will eat it. Wow! They are fun to observe. They break the rules of the animal kingdom. An 18th century naturalist, Carl Linnaeus, said that Venus flytraps, and other plants that feasted on animal flesh, went “against the order of nature as willed by God.” By contrast, the Venus flytrap was a personal favorite of Darwin’s. He wrote in Origin of the Species, “I care more about Drosera than the origin of all the species in the world.”

Wild Venus flytraps are native to the swampy pine savannah in the Carolinas—North and South. This is the only place on earth where these bizarre plants grow wild.  Commercial varieties, or cultivars grown in greenhouses, have the nicknames Big Mouth, the Jaws, the Royal Red and the Red Dragon.  They are available in assorted colors:

The International Union for Conservation of Nature (IUCN) lists the Venus flytrap as a vulnerable species. After it was overharvested in the 1990s, there were attempts to protect the rare plant by improving techniques to cultivate it and discourage people from collecting it in its native habitat. Venus flytraps are included under different categories, depending on the list; the United Plant Savers lists them as “at risk.”

For more information, check out these two blogs on Venus flytraps:

Carnivorous Plants: Artful Deceit

Interesting facts about Venus flytraps

Update: See also The Lure of Carnivorous Plants