Wetland plants – Discover-Nature

Carnivorous Plants

Plants and insects have myriad relationships to one another. Some are mutually beneficial, as when plants offer nectar to feed insects which in turn pollinate the plants. Other relationships only benefit the insects when they feed on leaves, stems, and roots. For carnivorous plants, preying on insects to fulfill their need for nitrogen and other nutrients benefits only the plants.

^{Venus flytrap, Dionaea muscipula by Len Worthington, Aug, 2016}

Pitcher plants are carnivorous, living in bogs and fens found in warm weather areas. In North America, most species are found along the southeastern coastal states from Texas to West Virginia. Bogs are depressions filled with rain or melted snow, while fens are similar but get their water from surface or groundwater. Both types of wetlands are low in oxygen and nitrogen, very acidic, and often quite cold. These characteristics slow down the rate of decay in the vegetation of the wetland, further reducing the availability of nitrogen which is a vital component of chlorophyll, the compound used by plants, along with water, carbon dioxide, and energy, to photosynthesize sugar for food.

^{Tracy’s sundew, Drocera tracyi by Matthew Paulson, May 2022; Venus flytrap, Dionaea muscipula by Judy Gallagher, Jun 2022; White-topped pitcher plant, Sarracenia leucophylla, showing downward hairs by Aaron Carlson, Sep 2013}

Carnivorous plants use several strategies to attract and trap insects. Pitfall traps have slippery faced leaves forming a funnel with a pool of digestive enzymes waiting at the bottom. Downward facing hairs on the leaves make it harder for insects to climb out. Some plants use an opposite strategy and cover their leaf surfaces with a sticky secretion, trapping any insects that land on them. Still others have a leaf-like structure made of two halves that snap together when an insect lands on an inner surface, trapping the insect inside. In both of the last two instances, digestive enzymes are then released to cover, kill, and break down the insect body for absorption by the plant.

^{White-topped pitcher plant, Sarracenia leucophylla, traps separated from flowers by NC Orchid, Apr 2016}

^{Two-spotted bumblebee, Bombus bimaculatus by Judy Gallagher, Jun 2022}

Carnivorous plants are insect pollinated and must be able to attract pollinators without trapping them. All of the plant species go through a dormant period as seasonal temperatures get cooler. Traps die back and are regrown when warmer weather returns. In several species, flowers bloom and attract pollinators with nectar, completing fertilization before traps develop. Other plants separate the flowers and traps by a physical distance. Traps usually lie close to ground level to attract crawling insects, and flowers are grown on top of tall stalks to attract flying insects. A third method is to make the flowers less attractive to potential prey, and make the traps less attractive to potential pollinators. This is achieved by using different colors, patterns, and scents on flowers and traps.

^{Metallic green sweat bee, Agapostemon sericeus by Dann Thombs, Aug 2008}

^{Cobra lily, Darlingtonia californica by Charles Peterson, Mar 2018}

Whether you are growing these unique plants at home or viewing them in a botanical garden or out in the wild, some of the plants and their pollinators to watch for include the white-topped pitcher plant, Sarracenia leucophylla and the two-spotted bumblebee, Bombus bimaculatus; the cobra lily, Darlingtonia californica and the mining bee, Andrena nigrihirta, Tracy’s sundew, Drosera tracyi and the metallic green sweat bee, Agapostemon sericeus, and the Venus flytrap, Dionaea muscipula and any of the hoverfly species, Toxomerus sp.

^{Bog landscape by Chris Moody, Jun 2009}

Duck Potato Salad

Walking around a freshwater marsh, we can observe dozens of plants and animals. Daily sunlight provides hours of energy, but it is only usable by the plants, which create their own food in a process called photosynthesis. Plants may be fully submerged, floating, or living above the water’s surface, but all are vital components of the food supply.

^{Marsh panorama by Beyond_Invisible, Getty Images}

Just as animals breathe, plants also need to exchange gases, taking in carbon dioxide and releasing oxygen. Plants living in a marsh, where they are fully or partially saturated with water, have developed several strategies for the gas exchange process. Spongy tissue is a universal adaptation of marsh plants. Both stems and leaves contain large airspaces surrounding food producing cells which are well distributed throughout the plant. Airspaces also keep the plants lightweight and enable stems, leaves and flowers to float on or reach above the water’s surface.

Floating wisps of green algae are primitive plants that have been on earth for over two billion years and are the basic food source for all life in the marsh. Millions of microscopic animals, crustaceans, insects, and small fish depend directly on green algae for their food. Green algae lack stems, leaves and flowers, but grow as long chains of nearly identical cells. Some algae are microscopic, some can be easily observed as green strands on or below the water’s surface and some grow to several hundred feet in length.

^{Duckweed forest pond by Sunsju, Aug 2019}

Duckweeds refer to a group of tiny, flowering plants that float on the surface of wetland areas. They reproduce by dividing their cells. This is a rapid process taking from 16 to 48 hours. In optimal growing conditions, with plenty of sunlight and nutrients available, the surface area of a pond can be covered in a very short period of time. Several species of pond plants grow long, narrow leaves with soft, nourishing cells providing a easy-to-eat and tasty treat for marsh dwellers. With large airspaces, these plants are able to stay afloat no matter how long they grow.

^{Spatterdock by Kirill Ignatyev, Jul 2011}

Plants with floating leaves, such as spatterdock, must have a method for preventing excess water from entering leaves and stems when they exchange gases. Plants have stomata, openings in the leaf where gases are exchanged. In terrestrial plants, stomata are located on the undersides of leaves to prevent rain from entering the opening. Floating leaves have stomata on the upper side of the leaf, providing far less exposure to water.

^{Water marigold by Gennady Alexandrov, May 2014}

Water marigold has two types of leaves, one that grows on the stem above the water’s surface and another that grows on the submerged stems. Leaves growing in air take in carbon dioxide and release oxygen through their stomata. Submerged leaves have very thin cell walls and exchange the same gases directly with the water surrounding them.

^{Arrowhead with bulb, -duck potato’, lower right, by Andriy Nekrasov, Getty Images}

Arrowhead is firmly anchored in the bottom of ponds, and has stems, leaves, and flowers growing above the surface. It reproduces by both seeds grown from pollinated flowers and bulbs grown on submerged stems. Bulbs remain submerged, attached to the stem and grow until they are mature enough to anchor themselves in the bottom silt and start another plant. While growing, the bulbs are very tasty and are a favorite food of many duck species, earning the nickname duck potatoes.

^{Wild celery, Vallisneria americana, by Schizoform, Jun 2022}

Wild celery produces both male and female flowers. Female flowers are attached to long stems that float on the water’s surface. Male flowers break off underwater and float to the surface unattached, where they are blown around until they meet a female flower, transferring pollen by contact. The pollinated flower coils downward back under the surface where the seeds develop and are released into the water to start a new plant wherever they land on the silt bottom.

Marsh plants come in many forms and each is well adapted to the unique conditions of the habitat in which they live.

Spring Wetland Vegetation

Early spring vegetation provides egg laying opportunities & protection

In early spring, when temperatures are still cool at night and daylight hours are just starting to lengthen, most plants are just starting to become active. Many amphibian and bird species also start their breeding activities at this time of year, and some of those depend on wetlands for egg laying sites, nesting material, food, and protection. Wetland vegetation creates important habitat for these species.

Emergent wetland at Kino Environmental Restoration project by Desert LCC, Aug 2018

Emergent plants are non-woody species that are rooted in wetland bottoms, but grow tall and emerge above the surface of the water. There are three categories of emergent plants that are important to pond life, including narrow-leaved emergents, broad-leaved emergents, and tall-robust emergents. Additional plants that affect wildlife populations in wetlands include floating plants, shrubs and trees.

Common bur reed, Sparganium eurycarpum, by USFWS Mountain-Prairie, Jul 2008

Common beggar’s ticks, Bidens frondosa, by Gertjan van Noord, Jul 2020

Marsh smartweed, Persicaria amphibia stipulacea, by Tom Wilberding, Aug 2020

Blue-joint grass, Calamagrostis canadensis, at Silver Lake, Utah, by Andrey Zharkikh, Aug 2014

Water willow, Justicia americana, by peganum, Jul 2017

Horsetail, Equisetum arvense, by delirium florens, May 2020

Narrow-leaved emergent plants are grasslike, with narrow stems and leaves, and grow to less than six feet in height. They come from the plant families that include sedges, Carex; rushes, Juncus; and bulrushes, Scripus. Some common narrow-leaved emergents of northern Illinois are common bur reed, Sparganium eurycarpum; horsetail, Equisetum arvense; reed canary grass, Phalaris arundinacea; and blue-joint grass, Calamagrostis canadensis. They provide cover for tadpoles and stems for perching birds to call from. Underwater stems are used to anchor frog egg sacs, and above surface leaves are used for egg laying by several species of dragonflies and damselflies.

Spot-tailed dasher, Micrathyria aequalis, on emergent vegetation by Allan Hopkins, Dec 2012

Eggs sacs anchored on emergent vegetation by JW112211, Apr 2006

Broad-leaved emergent plants are characterized by leaves almost as wide as they are long, and they grow to under three feet in height. Common species in northern Illinois include marsh smartweed, Persicaria amphibia stipulacea; common beggar’s ticks, Bidens frondosa; and water willow, Justicia americana. With broader leaves, these species provide excellent protection for adult and juvenile amphibians.

Cattail marsh at Jay Meiner Wetlands by Justin Meissen, Aug 2006

Tall-robust emergent plants are 5′ to 9′ tall when mature. Leaf and stem sizes vary greatly. In winter, some of the plants may die back or collapse, but many species grow in tightly packed stands where portions of the plant group will survive the entire winter. Examples in northern Illinois include narrow-leaved cattail, Typha angustifolia and broad-leaved cattail, Typha latifolia. In addition, common reed, Phragmites australis, is a highly invasive species found throughout our area.

Tadpole under duckweed by Helena, Jun 2007

Two other groups of plants are important to early spring wildlife. Shrubs, woody plants from 3′ to 9′ tall, and trees, woody plants over 9′ tall. Growing on wetland banks or in shallow water, trees and shrubs have branches and leaves that may be submerged or growing just above the surface. These provide perches for calling species, and some may be used for egg-laying sites. Common species in our area include blue-fruited dogwood, Cornus obliqua; silver maple, Acer saccharinum; and buttonbush, Cephelanthus occidentalis. Floating plants only grow on the surface where there is several inches of water. They are good indicators of water depth and the extent of open water in wetlands. They provide cover for many underwater eggs and juveniles. Duckweeds of the Lemna family and pond lilies in the Nuphar and Nymphaea families are common floating plants in this area.

Buttonbush, Cephelanthus occidentalis, by Jenny Evans, May 2008

Wetlands with emergent vegetation and stable water levels provide healthy habitat for bird, insect, and amphibian breeding populations. As you are out walking this spring, be sure to look at wetland vegetation and how it is used by the wildlife populations living there.

Cattails

Cattails are a familiar plant seen growing in wetland habitats throughout the area. Native to many parts of the world, including North America, South America, Africa and Eurasia, they provide food and protection for many species living in wetlands. Cattails are an emergent plant, with roots growing in soil underwater and the remainder of the plant emerging above the surface, into the air. Cattails prefer six to eighteen inches of water, although they can tolerate drought conditions as long as the soil remains moist.

Broad-leaved cattail, Typha latifolia by Tom Benson

Narrow-leaved cattail flowers, Typha angustifolia by Ryan Hodnett

There are two species of cattails common in Illinois. Broad-leaved cattail, Typha latifolia, and narrow-leaved cattail, Typha angustifolia, have many of the same characteristics and hybridize easily, so identification may be difficult. Stems are three feet to nine feet tall and are firmly anchored in the wet soil by a complex system of fine, tentacled roots; they are flanked by slightly shorter, narrow, upright, olive-green leaves. Separate groups of male and female flowers grow at the top of the stem. Yellow male flowers are located at the tip above a thick, velvety cluster of dark brown female flowers. The male flowers of broad-leaved cattails grow immediately above the female flowers, but on narrow-leaved cattails there is a space of several inches between the two groups.

Broad-leaved cattail flowers, Typha latifolia by Kevin Kenny

Both cattail species live in the same habitat and are aggressive spreaders. They utilize two different reproductive strategies. Rhizomes, roots growing horizontally along the soil surface, begin to spread in autumn. They cease growth during the colder temperatures of winter, but become active again in spring. Where the rhizome comes in contact with the soil, a new clone of the original plant is started. Clonal clusters grow in tight masses of up to a hundred stems. A second reproduction strategy is wind pollination. Pollen, a male sex cell, fertilizes female flowers. Seeds are then also spread by the wind. After pollen is dispersed, the male portion of the flower spike withers and falls off. The dark brown cluster of seeds may include up to 200,000 per stem. As seeds pull away from the stem, an attached silk plume billows out behind, allowing the seed to be borne long distances on steady breezes.

a quiet canoe trip on Isobel Lake…a Marsh Wren’s (Cistothorus palustris) desk amongst the reeds…Marsh Wren nest by Murray Foubister

Wetlands provide safe habitat for many species of spiders, insects, fish, turtles, birds and mammals. The denseness of cattail clusters keeps predators out while providing small pockets for homes. The area is a favorite for marsh wren, red-winged blackbird, yellow-headed blackbird, American coot and many species of rails and bitterns. Leaves are used for building nests and muskrat lodges. Young leaves provide food for many insects, mammals and birds. The carbohydrate-rich rhizome is an important food source for muskrat and geese. Seeds are rarely eaten, but seed heads provide over-wintering habitat for several moth larvae which in turn are a spring food source for many birds.

Muskrat with cattails by Michael B Smith

Early native Americans also enjoyed cattails in their meals. Flower spikes were roasted and served like corn cobs. Pollen was mixed with wheat flour to provide a nourishing base for bread. Today, leaves are woven into chair seats, rugs, and mats. Look for stands of cattails in nearby wetland communities, and observe the other species that live among them including ferns, rushes, sedges, grasses and the many animals that call these environments home.