Because there are three distinct types of wetlands in our area, there are three different plant communities that inhabit them. What they have in common is an ability to thrive in waterlogged conditions — therefore they are called 'hydrophilic' plants.

Marshes are easily recognised by their abundance of emergent vegetation, such as cattails (Typha spp.), bulrushes (Scirpus spp.), sedges (Carex spp.), Arrowhead (Sagittaria latifolia), Water Lilies (Yellow - Nuphar variegata and White - Nymphaea odorata), Blue Flag (Iris versicolor), and 'floaters' like Common Duckweed (Lemna minor). Not so easily seen are the submergent plants like pondweed (Potamogeton spp.) and Canada Waterweed (Elodea canadensis).

White Water Lily. Photo by Alan Ernst.

Arrowhead. Photo by Alan Ernst.

Marshes are also at risk because of non-native, invasive plants such as Purple Loosestrife (Lythrum salicaria) and the Common Reed (Phragmites australis).

Swamps in the Hamilton area are dominated by Red Maple (Acer rubrum) and Silver Maple (Acer saccharinum) but you can also find Ash (Fraximus nigra and F. pennsylvanica) and Elm trees(Ulmus americana). In some areas these trees exhibit lower trunks and roots that have adapted to the wet surroundings by forming what are called buttresses; strange raised roots that resemble knees. There are also swamps that are dominated by Eastern White Cedar (Thuja occidentalis), with smaller numbers of Tamarack (Larix laricina) and White Pine (Pinus strobus). Sometimes swamps will have areas of both tree groups in different locations.

Below the tree canopy there are often limited numbers of shrubs such as Speckled Alder (Alnus incana), Winterberry Holly (Ilex verticillata), Labrador Tea (Ledum groenlandicum) and Sweet Gale (Myrica gale).

Herbaceous swamp plants include Blue Flag (Iris versicolor), Marsh Marigold (Caltha palustris), Water Arum (Calla palustris), Cardinal Flower (Lobelia cardinalis) and the orchids, Grass Pink (Calopogon tuberosus) and Showy Lady's Slipper (Cypripedium reginae).

Marsh Marigold in Cootes Paradise. Photo by Alan Ernst.

Showy Lady's Slipper. Photo by Alan Ernst.

Blue Flag. Photo by Alan Ernst.

Ferns also are abundant and common species include the Sensitive Fern (Onoclea sensibilis), and Royal Fern (Osmunda regalis).

Peatlands, such as Summit Bog at Copetown, are characterised by a uniform, low shrub cover composed mostly of Leatherleaf (Chamaedaphne calyculata) with smaller numbers of Sweet Gale (Myrica gale), Labrador Tea (Ledum groenlandicum) and others.

Below this more visible layer is a carpet of peat mosses (such as Sphagnum angustifolium, S. fuscum, S. nemoreum and S. fallax). These mosses are bryophytes, plants without vascular tissue, and the Sphagnum, or peat mosses are key species for identifying peatland habitats.

In between the mosses and the dominant shrubs there are plants that are considered shrubs because they have woody stems, but which are small and sometimes not easily noticed such as Small Cranberry (Vaccinium oxycoccos).

Many bogs and fens may have a few trees or stands of trees where it is drier. These trees are typically Tamarack (Larix laricina) and Black Spruce (Pica mariana).

Finally there are herbaceous plants, some of which are well known for their insect-eating lifestyle like Pitcher Plant (Sarracenia purpurea) and Round-leaved Sundew (Drosera rotundifolia).

Sundew plant in Crieff Bog. Photo by Alan Ernst.

Pitcher Plant in Summit Bog. Photo by Barry Cherriere.

Cotton Grass. Photo by Alan Ernst.

You can also find Cotton Grass (Eriophorum spp.) that grows in tufts here and there.