marsh – Discover-Nature

Over the past several days, there has been a lot of activity in our backyard pollinator garden in the area surrounding the buttonbush, Cephalanthus occidentalis. This native shrub is a multi-stemmed flowering species that can grow from 3′ to more than 12′ tall. It needs lots of sunshine and prefers moist soils. Found in many habitats including sub-tropical swamps, shrub swamps in the northeast and upper Midwest, and southern and northern floodplain forests east of the Mississippi, this species prefers swampy backwater areas, marshes, wet meadow and bogs.

^{Buttonbush, Cephalanthus occidentalis, scaly bark by Lalit Mohan Sethee, Getty Images}

^{Buttonbush, Cephalanthus occidentalis, whorled leaves by loonyhiker, Oct 2010}

Newer stems are green, but quickly turn dark brown to almost black, becoming scaly with age. Leaves are opposite or whorled around the stem, each one protruding at a slightly different angle than the one above. It is thought that this arrangement provides maximum exposure of the plant’s total leaf surface to the sun.

^{Buttonbush flowers by DonArnold, Jul 2023}

^{Bumblebee on buttonbush by DonArnold, Jul 2023}

The flower clusters appear as small balls between 1/2″ and 1″ in diameter, with over 200 spikes poking outward covering their entire surface. Each spike is actually an individual flower. Flowers are closely grouped together and exude an intense, sweet fragrance. The plant reproduces through a two-stage cycle where pollen is produced and falls onto the immature pistil. As visiting insects brush through the closely grouped flowers, pollen rubs off onto their bodies. Once the pollen is gone, the pistil matures and becomes sticky at the end. As other insects arrive, pollen from other plants is picked up by the sticky end to pollinate the plant.

After pollination is complete, and the flowers drop off the plant, the ball-shaped seedhead turns completely brown. Unless it is brushed off by a passing animal or it is eaten, the seedhead may remain with the plant through the entire winter season, dropping off in spring. Seeds will often disperse into wetland areas, floating to shore. Each seed ball contains two nutlets.

^{Red Admiral butterfly on buttonbush by DonArnold, Jul 2023; Honney bee on buttonbush by DonArnold, Jul 2023; Long-tongued tiger swallowtail on buttonbush by Owen Sholes, Getty Images}

Pollinators include many long-tongued insect species especially bumblebees, honey bees, tiger swallowtail butterflies and black swallowtail butterflies. In addition, over two dozen bird species utilize the shrub for food, shelter, and nest building material – most notably are wood ducks that use the plant’s structure to shelter their young. Amphibians and reptiles hide among clusters of buttonbush in wetland areas for protection during the breeding season. Several honey-producing bee species are attracted to its pollen and nectar.

^{Buttonbush, Cephalanthus occidentalis, by NC Wetlands, Aug 2018}

With more than a dozen buttonbush species worldwide, it is an easy plant find and get close to for observing its flowers and fruits, as well as the behaviors of the many animal species that frequent this shrub.

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.

Tag: marsh

Buttonbush

Duck Potato Salad