Open Wetlands Key

This is a dichotomous key to open wetland natural communities

Dichotomous keys work by making one of two choices. Start at number 1, and determine which of the descriptions best suits what you are looking at. Then click on the link under the "go to" column to take you to the next choice, and ultimately to the natural community description.

Number	Description	Go To
1	Tidal wetlands	2
1	Non-tidal wetlands	6
2	Saltmarshes: vegetation varies, saltmeadow cordgrass and/or smooth cordgrass present and often a major component; dominants also may include black-grass, sedges, etc.	3
2	Brackish to freshwater marshes; saltmeadow cordgrass and/or smooth cordgrass not prominent	4
3	Saltmarshes with saltmeadow cordgrass and/or smooth cordgrass totaling >35% cover, or with black-grass >35% cover; most other species clearly less abundant (not including low-growing species like goosetongue that may be extensive beneath the graminoids)	Spartina Saltmarsh
3	Saltmarsh cordgrass and/or black-grass are not strongly dominant, "canopy" vegetation more a mixture of graminoids and forbs; chair-maker's rush typically present, and may be dominant	Mixed Graminoid - Forb Saltmarsh
4	Shrubs dominant	Alder Floodplain
4	Herbaceous plants dominant	5
5	Brackish tidal setting; vegetation a mix of tall graminoids and rosette-forming forbs; freshwater cordgrass and/or wire rush usually present; obligate freshwater species such as cardinal flower, sweet flag, and pickerelweed absent	Brackish Tidal Marsh
5	Freshwater, near the upstream end of the tidal reach; vegetation graminoid-dominated, with wild rice and/or softstem bulrush typical; some obligate freshwater plants such as pickerelweed, cardinal flower, and/or sweet flag present	Freshwater Tidal Marsh
6	Submerged or floating-leaved aquatic vegetation; emergent plants, if present, are mostly those that die back below the water in autumn	7
6	Not as above; lakeshores, rivershores, bogs, fens, marshes that are not permanently underwater or, if so, are vegetated with emergent vegetation that remains through the winter	12
7	Plants with emergent leaves dominant	8
7	Plants with floating or submerged leaves dominant	10
8	Pickerelweed dominant among the emergent species	Pickerelweed - Macrophyte Aquatic Bed
8	Graminoids dominant among emergent species	9
9	Bulrushes and/or bayonet rush dominant	Bulrush Bed
9	Cattails dominant	Cattail Marsh
10	Some plants indicative of higher pH waters present, e.g. tapegrass, common waterweed, water stargrass, white water crowfoot, Robbins' pondweed, alpine pondweed, Vasey's pondweed, and straight-leaved pondweed; water-shield, pipewort, water lobelia, and pickerelweed absent or virtually so	Circumneutral - Alkaline Water Macrophyte Suite
10	Alkaline indicators absent; vegetation usually includes pipewort, water lobelia, pondweed species other than those listed above, and/or water-lilies	11
11	Vegetation mostly floating-leaved plants and/or submerged plants with aquatic stems floating in the water column; water-lilies and pondweeds typically dominant; depth varies	Water-lily - Macrophyte Aquatic Bed
11	Vegetation dominated by submerged plants (flower stalks may protrude) with leaves mostly on the substrate, often in rosettes; pipewort and water lobelia characteristic; water depth usually <1 m	Pipewort - Water Lobelia Aquatic Bed
12	Gently-sloping sandy or gravelly pondshores (usually of small ponds in outwash basins) of Southern Maine where natural water levels usually drop by late summer, exposing progressive bands of vegetation. From the upland edge, a band of shrubs is followed by three-way sedge, bayonet rush, and narrow-leaved goldenrod in the upper shore zone, then pipewort or other submerged aquatic species in the most flooded zone. Golden pert and meadow beauty are usually present as indicators (see couplet 22 for herbaceous lakeshore vegetation that is not in distinct bands)	Three-way Sedge - Goldenrod Outwash Plain Pondshore
12	Vegetation not obviously banded around a central pond whose water level drops through the season	13
13	Sphagnum and dwarf shrub dominated vegetation forming a thin layer over sloping bedrock (sometimes talus); only in subalpine or extreme maritime zones; peat may not remain saturated through the summer (may not be true wetlands)	14
13	Basin wetlands, or vegetation along lakeshores or rivershores; widespread	15
14	Bog-like vegetation forming a "blanket" on slightly sloping bedrock at the immediate coast, from Washington County east	Heath - Crowberry Maritime Slope Bog
14	Bog-like vegetation in subalpine setting, on steep slopes over bedrock or talus of mountain slopes (see couplet 24 for basin wetlands on summit plateaus)	Heath - Lichen Subalpine Slope Bog
15	Vegetation of rivershores or lakeshores, with the substrate primarily mineral rather than organic; mostly in linear bands following the shoreline; may be flooded seasonally, but out of the water for most of growing season	16
15	Wetlands in basins or along broad drainages, with organic soils or with an organic layer over mineral substrate; vegetation often covering a large part of the substrate; saturated through all or most of the year	24
16	On rivershores	17
16	On lakeshores or pondshores	23
17	Shrubs, mostly >1 m tall, predominate	18
17	Shrubs <1 m tall, or mixture of shrubs and herbaceous plants, predominate	19
18	Alder is dominant or co-dominant; virgin's bower is present	Alder Floodplain
18	Dogwood and willows predominate	Dogwood - Willow Shoreline Thicket
19	Mixed shrub-herb vegetation on sloping eroding river shores where substrate is constantly saturated by groundwater seepage; calciphilic fen species present, e.g., grass-of-Parnassus, Kalm's lobelia, sticky false asphodel; bryophyte layer at least locally well developed, with species other than Sphagnum dominant	Circumneutral Riverside Seep
19	Vegetation of almost-flat rivershores or Lakeshore Sand/Cobble Beaches (see couplet 23), substrate gravelly to sandy and not constantly saturated to the surface by seepage; bryophytes sparse or absent	20
20	Tall graminoids and forbs dominant, forming a dense meadow; shrubs, if present, are rarely taller than the herbs; bluejoint, spotted joe-pye weed, and flat-topped white aster characteristic	Bluejoint Meadow
20	Vegetation more sparse and not dominated by bluejoint	21
21	Beach heather a locally prominent dwarf shrub; islands of gray birch usually present; little bluestem one of the more common graminoids; documented in Maine only from Saco River drainage	Hudsonia River Beach
21	Beach heather and little bluestem are absent or incidental	22
22	Sand cherry and roses the dominant dwarf shrubs, Laurentian/Cordilleran plants such as Huron tansy, alpine sweet broom, and alpine milk-vetch often present; in Maine documented only on far northern rivers	Sand Cherry - Tufted Hairgrass River Beach
22	Tufted hairgrass, twisted sedge, or other forbs and graminoids are dominant; statewide	Twisted Sedge Cobble Rivershore
23	Sparse vegetation on lakeshore cobble or sand beaches; silverweed typical, beach heather, or golden heather may be present	Lakeshore Sand/Cobble Beach
23	Patchy or sparse vegetation on subalpine gravelly pondshores	Mountain Alder - Bush-honeysuckle Subalpine Meadow
24	Bogs and fens: substrate is accumulated peat (undecayed to partially decayed), usually >0.5 m deep and with extensive Sphagnum on the surface, sometimes floating over water; constantly saturated	25
24	Marshes: substrate is mineral soil, often with a surface layer of well-decomposed organic matter (peat, typically sedge-derived, may be >0.5 m thick but is generally less); Sphagnum may be present but does not form an extensive deposit; some remain saturated, but many dry out for at least part of the growing season	37
25	Alpine or subalpine basin peatlands, near or above treeline	Cotton-grass - Heath Alpine Bog
25	Lower elevation wetlands	26
26	Bryophyte-dominated, often in raised peatlands; substrate wet and unstable; vascular plants usually <25% cover and limited to low-growing species e.g. cranberries, horned bladderwort, and white beak-rush; very dwarfed leatherleaf or other ericads may be present	Bog Moss Lawn
26	Shrub and/or herb cover more extensive; vegetation not primarily bryophytes	27
27	Shrub cover (including dwarf shrubs) exceeds graminoid cover	28
27	Graminoid cover equals or exceeds shrub cover, including dwarf shrubs	33
28	Vegetation dominated by tall shrubs (mostly >1.5 m); mountain holly, alder, and wild calla characteristic; standing water usually present among hummocks of Sphagnum; in peatlands often at the upland/peatland interface	Mountain Holly - Alder Woodland Fen
28	Vegetation dominated by herbs or shrubs mostly under 1m tall, typically including abundant ericads; mountain holly and alder may be present but are not dominant	29
29	Shrubby cinquefoil a prominent shrub, and other circumneutral indicators present, e.g. livid sedge, grass-of-Parnassus, and/or Kalm's lobelia	Shrubby Cinquefoil - Sedge Circumneutral Fen
29	Shrubby cinquefoil absent (or scarce) and other circumneutral indicators lacking	30
30	Shrubs relatively tall (often >1 m) with sweetgale, hardhack, and/or meadowsweet prominent; leatherleaf often present but other ericads not abundant; typically in standing shallow water without a continuous Sphagnum carpet	Sweetgale Mixed Shrub Fen
30	Vegetation dominated by ericads (though sweetgale often present), usually well under 1 m tall; bogs and fens on well developed Sphagnum carpets	31
31	Low bog vegetation with dwarf huckleberry locally dominant (often patchy), >20% cover; black crowberry and/or deer-hair sedge also present though not necessarily at high cover; graminoid cover may be relatively high (often >25%); coastal (up to 15 miles or so inland)	Huckleberry - Crowberry Bog
31	Other shrubs dominant, or if dwarf huckleberry dominant then neither black crowberry nor deer-hair sedge present; both coastal and inland	32
32	Weakly minerotrophic fen conditions (vegetation mostly in contact with the water table), with leatherleaf (or a combination of leatherleaf with bog rosemary and/or sweetgale) the dominant shrub; other shrubs and sedges mixed in; graminoid cover variable	Leatherleaf Boggy Fen
32	Ombrotrophic bog conditions (vegetation mostly raised above the water table), with sheep laurel, Labrador tea, and/or rhodora together more abundant than leatherleaf and sweetgale; graminoid cover rarely exceeds 15%	Sheep Laurel Dwarf Shrub Bog
33	Sedge-dominated lawns, deer-hair sedge and/or coast sedge characteristic; centrally located on raised (ombrotrophic) plateau bogs within about ten miles of the coast, Hancock County east	Deer-hair Sedge Bog Lawn
33	Fen (minerotrophic) setting, areas sometimes transitional to bogs, but not the central lawn of a coastal plateau bog	34
34	Fens with circumneutral indicators e.g. livid sedge, yellow sedge, grass-of-Parnassus, Kalm's lobelia, and/or shrubby cinquefoil, usually with more than one indicator species	Shrubby Cinquefoil - Sedge Circumneutral Fen
34	Circumneutral indicator species absent or virtually so	35
35	Vegetation dominated by tall sedges: dominant species are slender sedge, beaked sedge, and/or lake bank sedge; or rarely tussock sedge or inflated sedge	Mixed Tall Sedge Fen
35	Slender sedge, beaked sedge, lake bank sedge, and inflated sedge not the dominant sedges, vegetation mostly lower	36
36	Carpets of low sedges over very wet Sphagnum substrate, with mud sedge, podgrass and white beak-rush characteristic; dwarf or creeping shrubs may be mixed with the sedges but are sparse (<20% cover)	Low Sedge - Buckbean Fen Lawn
36	Sedges mixed with dwarf shrubs, usually >20% shrub cover; white beak-rush often present, but mud sedge and podgrass not; dominant sedges include few-seeded sedge, coast sedge, Michaux's sedge white beak-rush, and/or narrow-leaved cotton-grass	Sedge - Leatherleaf Fen Lawn
37	Tussock sedge is the dominant herbaceous species (>30% cover, and usually >50%); shrub cover usually <30%; standing water between hummocks for much of season	Tussock Sedge Meadow
37	Herb component dominated by species other than tussock sedge	38
38	Shrub cover exceeds herb cover	39
38	Herb cover exceeds shrub cover	41
39	Mixture of herbs and shrubs; dominant shrubs are not alder, sweetgale, or ericads, but are more often buttonbush or bog willow	Mixed Graminoid - Shrub Marsh
39	Alder, sweetgale, and/or ericads are the dominant shrubs	40
40	Alders strongly dominant, >20% cover; ericads absent or virtually so	Alder Shrub Thicket
40	Sweetgale and/or heath shrubs dominant, alders clearly subordinate	Sweetgale Mixed Shrub Fen
41	Bluejoint dominates herb component, >50% cover; shrubs <25% cover	Bluejoint Meadow
41	Mixture of herbs and shrubs (herbs 25-95%, shrubs 0-70% cover), without dominance of tussock sedge, bluejoint, or alder	Mixed Graminoid - Shrub Marsh

 

Back to Top