Keys to Maine Natural Community Types (April 2004) (Note: Page numbers refer to an earlier version of the classification and should not be used) First, a Key to the Keys: 1. Trees forming > 25% canopy, or if less (rarely), then canopy and subcanopy (everything > 3 m tall) total > 30% cover: forests and woodlands 2 1. Tree canopy < 15%, or if slightly more, then canopy and subcanopy together total < 30% (usually < 15%); some small islands of trees may be present: open (non-wooded) vegetation 3 2. UPLAND: soils not saturated throughout season, Sphagnum covering < 10% of ground surface. Exception: in summit or ledgy types the "soil" may be thin pockets of peat in bedrock depressions, and may be saturated; these are treated as uplands WOODED UPLANDS KEY (p. 1) 2. WETLAND: soils saturated throughout season and/or Sphagnum covering > 10% of ground surface (see note re exceptions in other half of couplet); usually basins or streamsides WOODED WETLANDS KEY (p. 6) 3. UPLAND: soils not saturated throughout season, Sphagnum covering < 10% of ground surface. Exception: sometimes in open summit or other ledgy types the "soil" is thin peat pockets over bedrock, and often saturated; these are treated as uplands OPEN UPLANDS KEY (p. XX) 3. WETLAND: soils saturated throughout season and/or Sphagnum covering > 10% of ground surface (see note re exceptions in other half of couplet); usually basins or streamsides OPEN WETLANDS KEY (p. XX) WOODED UPLANDS KEY 1. Conifer forests and woodlands: deciduous trees1 < 25% RD2 2 1. Deciduous or mixed forests and woodlands: deciduous trees > 25% RD 24 2. Conifer forests: tree cover usually > 65%, lower layers generally more sparse than canopy (except for dense patches of tree regeneration in canopy openings); area lacks a well-developed low shrub layer of lowbush blueberry (Vaccinium angustifolium) velvet-leaf blueberry (V. myrtilloides), black huckleberry (Gaylussacia baccata), sheep laurel (Kalmia angustifolia), or black chokeberry (Photina melanocarpa)3; substrate various, but often mineral soil, usually not a thin organic layer over bedrock 3 2. Conifer woodlands: tree cover usually < 65%, as low as 20% (occasionally to ~80%), trees more-or-less open grown; low shrub layer of lowbush blueberry, huckleberry, sheep laurel, and/or chokeberry prominent (>15% cover), or sometimes bracken fern (Pteridium aquilinum) prominent (> 7% cover) instead; ground cover may feature fruticose lichens; substrate bedrock, with a thin layer of mostly organic soil typically < 15 cm deep 14 Conifer forests 3. Hemlock and/or pines dominant (near the coast, northern white cedar occasionally co-dominant) 4 3. Spruce and/or fir dominant 8 4. Hemlock dominant; red spruce, white pine, and/or cedar often present, sometimes co-dominant; stands may be either coniferous or mixed, strongly coniferous stands with very sparse herb and bryoid layers Hemlock Forest (p. XX) 4. Hemlock not dominant 5 5. Northern white cedar dominant; rocky hillslopes White Cedar Woodland (p. 60) (some closed-canopy examples of the type) 5. Pines dominant 6 6. Jack pine dominant, or co-dominant with black spruce; known only from western Maine Jack Pine Forest (p. XX 6. Red pine or white pine dominant; more widespread 7 7. White pine dominant (highest basal area); red spruce, hemlock, and/or northern white cedar often present and may be nearly co-dominant White Pine - Mixed Conifer Forest (p. XX) 7. Red pine dominant (highest b.a.); red spruce, white pine, (or coastally, northern white cedar) often present, may be nearly co-dominant Red Pine - White Pine Forest (p. XX) 8. Balsam fir dominant, heart-leaved paper birch and/or mountain ash often common, subalpine or coastal 9 8. Red and/or black spruce dominant 10 9. Coastal; white spruce often present Maritime Spruce - Fir Forest (p. XX) 9. Montane; white spruce absent Fir - Heart-leaved Birch Subalpine Forest (p. XX) 10. Variable canopy closure; black spruce or red-black hybrids often present; red pine occasionally present; heath shrubs prominent in herb layer (often >25% cover, may be very dense); usually on level, well-drained glacial deposits, sometimes with patches of saturated-soil and peat moss pockets in hummocky topography Spruce - Heath Barren (p. XX) 10. More or less closed canopy with mixtures of red spruce, black spruce, or other conifers; heath shrubs and herbs sparse (less than 20% cover), or if more, then with northern wood-sorrel (Oxalis montana), bluebead lily (Clintonia borealis), tree regeneration may be dense in gaps 11 11. Red spruce, black spruce, or hybrids on level, poorly drained soils; wetland plants and peat mosses may be frequent, bryoids abundant (>50% cover) Spruce - Fir - Cinnamon Fern - Forest (p. XX) 11. Upland sites on till, bedrock, or talus), with red spruce or white spruce dominant; yellow birch and balsam fir may be occasional; wetland plants absent except in small seeps and ravines 12 12. Herb layer with locally extensive cover of herbaceous species (often in patches), including northern wood-sorrel (Oxalis montana), bluebead lily (Clintonia borealis), rose twisted-stalk (Streptopus lanceolatus), or mountain wood-fern (Dryopteris campyloptera); bryoid layer >20%, with feather-mosses prominent; northern/montane areas Spruce - Fir - Wood-sorrel - Feather-moss Forest (p. XX) 12. Herbs and dwarf shrubs sparse (<10% cover each); herb layer may include dense regeneration patches 13 13. Coastal (within 1/4 mi. of the coast); white spruce often present, especially near coastline; bryoid layer >15% cover and not dominated by broom-mosses (Dicranum, Dicranella spp.) Maritime Spruce - Fir Forest (p. XX) 13. Widespread inland, may be near-coastal; both herb and bryoid layers very sparse; what bryoids are present include a large proportion of broom-mosses and pincushion moss (Leucobryum glaucum) Spruce - Fir - Broom-moss Forest (p. XX) Conifer woodlands 14. Northern white cedar the dominant tree species, usually twice as abundant as any other tree species White Cedar Woodland (p. XX) 14. Other species dominate tree layer 15 15. On talus, spruce dominant Spruce Talus Woodland (p. XX) 15. On bedrock (or, less commonly, sand or glacial till), various dominants 16 16. Mixture of conifer species, each < 50% RD; or woodlands dominated by white pine or red pine 17 16. Pitch pine, jack pine, or spruce each > 60% RD 18 17. Canopy dominated by red spruce or white pine (> 60% RD), or by a mixture of conifers with none dominant, red spruce usually present Red Spruce - Mixed Conifer Woodland (p. XX) 17. Red pine dominant in canopy Red Pine Woodland (p. XX) 18. Jack pine dominates canopy Jack Pine Woodland (p. XX) 18. Other conifers dominate canopy; jack pine usually absent altogether 19 19. Black spruce the most abundant canopy tree 20 19. Pitch pine the most abundant canopy tree 21 20. Woodlands on bedrock, often coastal or on upper summits inland Black Spruce Woodland (p. XX) 20. Woodlands or forests on level or gently sloping till, occasionally with a thick organic layer Spruce - Heath Barren (p. XXX) 21. Open woodlands on ledge; trees often stunted Pitch Pine Woodland (p. XX) 21. Open woodlands or sometimes almost closed forest, on sandy soil 22 22. Dunes or backdune areas along the immediate coast; bayberry almost always present .................. Pitch Pine Dune Woodland (p. XX) 22. On glacial deposits, not dunes; inland or at least not at the immediate shoreline 23 23. Scrub oak extensive and locally dominant, making foot-travel difficult Pitch Pine - Scrub Oak Barren (p. XX) 23. Scrub oak absent or sparse, foot-travel easier Pitch Pine - Heath Barren (p. XX) Deciduous or mixed forests and woodlands 24. Forest seasonally saturated and/or discharging groundwater for significant periods during the growing season... 25 24. Forest not seasonally saturated or discharging groundwater 27 25. Forest on gentle to moderate slope or flat bench within upland setting; discharging groundwater for significant periods during the growing season; dominant trees include ashes, sugar maple, red maple, yellow birch, or hemlock; jewel-weed (Impatiens capensis) often present..... Hardwood Seepage Forest (p. XXX) 25. Forest saturated and flooded in the spring and adjacent to larger streams and rivers; ferns such as Ostrich fern (Matteucia struthiopteris) and royal fern (Osmunda regalis) frequent... 26 26. Floodplain forests with silver maple dominant and conifers absent or very sparse; usually along medium to large rivers. Herb layer includes ostrich fern (Matteucia struthiopteris) and other ferns. (Basswood - Ash - Red Maple Floodplain Forests (Provisional) (p. 231) may key here if silver maple is co-dominant.) Silver Maple Floodplain Forest (p. XX) 26. Other hardwoods dominant (not silver maple) 27 27. High floodplain or terrace forests along medium to larger rivers in southern and central Maine, most often with sugar maple or red oak dominant, sometimes with yellow birch or ash dominant; on larger rivers this type is often found adjacent to but at slightly higher elevation than silver maple floodplain forests (Basswood - Ash - Red Maple Floodplain Forests (Provisional) (p. XXX) may key here.) Hardwood River Terrace Forest (p. XX) 27. Floodplain with balsam poplar dominant or co-dominat with American elm and ash; northern Maine Balsam Poplar Floodplain Forest (p.XXX) 28. Open deciduous woodlands (tree cover <65%) with birches, red oak, red maple, or ironwood dominant (Ironwood - Oak - Ash Woodlands may occasionally have a forest canopy >65% but they will key here: check description in couplet 27 below). 29 28. Deciduous or mixed closed-canopy forests (tree cover >65%) or mixed woodlands 30 29. Hillside or low summit woodlands dominated by red oak, without much ironwood or sugar maple, and with a heath shrub and bracken fern (Pteridium aquilinum) understory Oak - Pine Woodland (p. XX) (variant of the type with little or no pine) 29. Not as above 30 30. Open to closed canopy woodlands on glacial till or outwash; early successional deciduous trees dominant (aspen, white/gray birches, red maple), red oak <40% RD (rarely up to 50%), conifers <30% RD Aspen - Birch Woodland/Forest Complex (p. XX) 30. Open woodlands on talus or thin-soiled hilltops rather than till or outwash 31 31. Woodlands on talus or thin-soiled hilltops and upper slopes; ironwood and oaks dominant (the former as either canopy or subcanopy), sugar maple occasionally common, and basswood often present but not abundant; with enriched site indicators e.g. round-leaved dogwood (Cornus rugosa), herb Robert (Geranium robertianum), hepatica (Anemone americana), columbine (Aquilegia canadensis), blue-stem goldenrod (Solidago caesia), wide-leaved sedge (Carex platyphylla) Ironwood - Oak - Ash Woodland (p. XX) 31. Woodlands on talus; birches the most abundant tree; oaks and ironwood may be present but less abundant; enriched site indicators absent or very incidental Birch - Oak Talus Woodland (p. XX) 32. Deciduous component dominated by northern hardwood species (beech, yellow birch, sugar maple, occasionally ash); red oak < 30% RD 32 32. Deciduous component dominated by oak, white or gray birch, red maple, and/or aspen, rather than northern hardwood species 38 33. Mixed forests with conifers >25% RD 34 33. Deciduous forests, conifers <25% RD 37 34. Red spruce the dominant conifer Spruce - Northern Hardwoods Forest (p. XX) 34. Hemlock or white pine the dominant conifer 35 35. Hemlock the dominant conifer Hemlock Forest (p. XX) (mixed variant) 35. White pine the dominant conifer 36 36. One or more northern hardwood species (beech, yellow birch, sugar maple) mixed with red oak and conifers; northern hardwood RD > 15% Red Oak - Northern Hardwoods - White Pine Forest (p. XX) 36. Canopy almost entirely red oak and white pine (occasionally red spruce), sometimes mixed with red maple; northern hardwoods sparse Oak - Pine Forest (p. XX) 37. Sugar maple dominant or co-dominant; white ash (rarely green ash) and/or basswood >10% RD; herbs >40% cover, with rich site herbs such as Dutchman's breeches (Dicentra cucullaria), maidenhair fern (Adiantum pedatum), pale jewel-weed (Impatiens pallida), blue cohosh (Caulophyllum thalictroides) common; typically small acreages in sheltered sites (coves) or where calcium-enriched soils have accumulated Maple - Basswood - Ash Forest (p. XX) 37. Some combination of beech, sugar maple, and yellow birch dominates the canopy; ash and basswood absent or very minor; herb layer rarely >40% cover except for tree seedlings; rich site herbs absent; environmental settings various, may cover large areas Beech - Birch - Maple Forest (p. XX) 38. Early successional deciduous trees dominant (aspen, white/gray birches, red maple), red oak <40% RD (rarely up to 50%), canopy closure variable from very open to almost closed; conifers <30% RD Aspen - Birch Woodland/Forest Complex (p. XX) 38. Oaks >50% RD, or if less then canopy >35% coniferous 39 39. White oak, chestnut oak, and/or hickories present; southern Maine 40 39. White oak, chestnut oak, hickories absent or virtually so; statewide 42 40. Chestnut oak dominant or at least common; open-canopy woodlands (<65% canopy) Chestnut Oak Woodland (p. XX) 40. Other oaks dominant 41 41. White oak and red oak dominate canopy; hickory essentially absent White Oak - Red Oak Forest (p. XX) 41. White oak and red oak present and may be dominant, but shagbark hickory (and sometimes bitternut hickory) also present Oak - Hickory Forest (Provisional) (p. XXX) (Note: It is questionable whether these two types are distinct in Maine.) 42. Closed-canopy forests with northern hardwood species (usually beech or sugar maple) >20% RD, may be co-dominant with red oak Red Oak - Northern Hardwoods Forest (p. XX) 42. Beech, sugar maple, and white ash <10% RD each 43 43. Woodland structure: open canopy (<60% closure, occasionally more), trees well-spaced and often stunted; well-developed herb layer (>15% cover of dwarf shrubs and >5% cover of herbs), with graminoids often abundant and typical closed-forest species essentially absent Oak - Pine Woodland (p. XX) 43. Forest structure: canopy closure >70% and understory somewhat sparse, with dwarf shrubs much less than 15% cover; herbs include typical forest species such as Indian cucumber-root (Medeola virginiana) and wild-oats (Uvularia sessilifolia) .........................................................................Oak - Pine Forest (p. XX) WOODED WETLANDS KEY 1. Peat-substrate wetlands with an herb layer dominated by either peatland plants, such as heath shrubs, cotton-grasses (Eriophorum spp.), white beak-rush (Rhynchospora alba), or three-seeded sedge (Carex trisperma), or by cedar, spruce, or fir regeneration with peatland plants as the most abundant herbs and shrubs; Sphagnum usually > 25% of ground surface; on peat substrates (peat >30 cm deep, usually more), or rarely with thinner peat over mineral soil; not on slopes 2 1. Mineral-soil or, less commonly, peat-based wetlands with herb layer dominated by plants other than the peatland plants listed above; Sphagnum may be present on ground surface, but is generally < 20% cover and rarely forms a peat deposit of more than 15 cm; in drainages or on gentle slopes 9 2. Red maple dominant in canopy, or co-dominant with larch (less commonly, spruce); occasionally, larch may be dominant and red maple far less abundant; canopy closure usually <50%, occasionally somewhat higher (to 65%) Red Maple Wooded Fen (p. XXX) 2. Conifers other than larch dominant in canopy 3 3. Northern white cedar dominant in canopy 4 3. Other conifers dominant 5 4. Closed-canopy or nearly closed-canopy forests (almost always >60% canopy); heath shrubs <15% cover; usually in poorly drained basins where they may occupy most of the basin, rather than occurring as part of a larger peatland vegetation complex Northern White Cedar Swamp (p. XX) 4. Canopy more open (usually <50%); partially wooded fens that are part of a larger peatland vegetation complex; heath shrubs or other dwarf shrubs usually >15% cover Northern White Cedar Woodland Fen (p. XXX) 5. Atlantic white cedar dominant or at least common 6 5. Atlantic white cedar absent (or very incidental) 7 6. Closed-canopy (or nearly so) forests, >60% tree cover; shrubs only patchily abundant in openings Atlantic White Cedar Swamp (p. XX) 6. More like an open bog, with trees patchy to sparse (<50% cover) and mostly stunted; abundant ericaceous shrubs Atlantic White Cedar Bog (p. XXX) 7. Pitch pine the dominant tree (though black spruce may be present); uncommon, southern Maine Pitch Pine Bog (p. XXX) 7. Black spruce are the dominant trees (may be stunted) 8 8. Peatland setting; organic soil (peat) usually > 50 cm deep; larch may be co-dominant; statewide and common Spruce - Larch Wooded Bog (p. XXX) NOTE: Spruce - Fir - Cinnamon Fern Forests with an unusually deep peat layer may key here (p. XX) 8. On mineral-soil flats in colder regions; substrate usually includes at least patches of poorly drained mineral soil, sometimes with a shallow peat layer (< 30 cm deep), sites often undulate with both wetland and upland patches; downeast and NW Maine Spruce - Heath Barren (p. XX) 9. Conifers dominant (>50% of canopy) 10 9. Deciduous or mixed forests with conifers <50% of the canopy 12 10. Atlantic white cedar dominant Atlantic White Cedar Swamp (p. XX) 10. Other conifers dominant 11 11. Red spruce or black spruce the most abundant conifer; red maple may be up to 40% RD Spruce - Fir - Cinnamon Fern Forest (p. XX) 11. Northern white cedar the most abundant conifer; red maple may be common here as well Cedar - Spruce Seepage Forest (p. XX) 12. Black willow a dominant tree; shrub layer usually well developed Black Willow - Alder Floodplain (p. XXX) 12. Black willow absent or very minor (black willow may form a fringe on the channel edge of some Silver Maple Floodplain Forests) 13 13. Silver maple, red maple, or balsam poplar the most abundant hardwoods, black gum absent; wetlands on alluvial flats bordering rivers or permanent streams 14 13. Other hardwoods (yellow birch, sugar maple, black gum, ash, red oak) more abundant than silver or red maple, or at least co-dominant with them; wetland setting various.. 17 14. Floodplain forests with silver maple dominant, and conifers absent or very sparse; usually along third-order or larger streams/rivers (Basswood - Ash - Red Maple Floodplain Forests (Provisional) (p. 231) may key here if silver maple is co-dominant.)..........................................Silver Maple Floodplain Forest (p. XX) 14. Red maple, American elm, or balsam poplar dominant in floodplain or basin adjacent to smaller stream. 15. Balsam poplar dominant or co-dominant with American elm and ash. Floodplain species such as ostrich fern and Virgin's bower present; northern Maine... .............................................Balsam Poplar Floodplain Forest (p. XXX) 15. Red maple, yellow birch, or hemlock dominant .............................................16 16. Red maple dominant, silver maple and musclewood more or less absent; conifers may be >25% of canopy; in various settings, such as low basins and along small to medium-sized rivers and streams Red Maple - Sensitive Fern Swamp (p. XXX) 16. High floodplain or terrace forests along medium to large rivers, most often with sugar maple or red oak dominant, sometimes with yellow birch or ash dominant; herb layer includes ostrich fern (Matteucia struthiopteris) and a mixture of wetland and upland species; often found adjacent to but at slightly higher elevation than silver maple floodplain forests (Basswood - Ash - Red Maple Floodplain Forests (Provisional) (p. XXX) may key here.)........................ Hardwood River Terrace Forest (p. XX) 17. Hardwood or hemlock-hardwood swamps in small, often isolated basins; shrub layer of highbush blueberry (Vaccinium corymbosum) or winterberry (Ilex verticillata); red maple common, black gum often present Hemlock - Hardwood Pocket Swamp (p. XXX) 17. Hardwood or hemlock-hardwood seepage forests on gentle slopes or discharge areas at level breaks in a slope; yellow birch, green ash, brown ash and/or white ash common in the canopy; may be co-dominant with red maple; highbush blueberry, winterberry, and similar shrubs absent or very sparse Hardwood Seepage Forest (p. XXX) OPEN UPLANDS KEY 1. Vegetation along rivershores, lakeshores, or the immediate Atlantic coast ......................2 1. Vegetation not associated with shores, most often on mountains, lower summits and rocky slopes ........................................................................................................8 2. Vegetation along the immediate Atlantic coast, subject to salt spray or occasional storm tides ................................................................................................................3 2. Inland vegetation ...........................................................................................7 3. Sandy or gravelly beach vegetation, either sparse or grass-dominated ............................4 3. Vegetation on shoreline bedrock, or with >25% shrub cover ........................................5 4. Sparse forb-dominated vegetation on loose sand, gravel or cobble near and above the high tide line; sea-kale (Cakile edentula) and beach-pea (Lathyrus japonicus) characteristic.......... ......................................................................................Beach Strand (p. 154) 4. Grass-dominated dune and tidal-edge vegetation on sand, dominated by beach grass (Ammophila breviligulata) or (downeast) Virginia wild rye (Elymus virginicus) ................................................................................... Dune Grassland (p. 146) 5. Sparse herb-dominated vegetation in bedrock crevices and depressions; seaside goldenrod (Solidago sempervirens) and goosetongue (Plantago maritima) typical ........................................Seaside Goldenrod - Goosetongue Open Headland (p. 148) 5. Cover more extensive, with shrubs or dwarf shrubs >25% cover ..................................6 6. Mats of dwarf shrubs, such as crowberry (Empetrum nigrum), lowbush blueberry (Vaccinium angustifolium), Velvet-leaf blueberry (V. myrtilloides) and cranberries (Vaccinium macrocarpon, V. vitis-idaea) punctuated by sparse taller shrubs and forbs; more common downeast.............................................Crowberry - Bayberry Headland (p. 136) 6. Mat-forming shrubs limited, most shrubs 1 m or so tall (or taller); bayberry (Myrica pensylvanica) and roses most characteristic; coastwide ........................................................Rose - Bayberry Maritime Shrubland (p. 118) 7. Lakeshore beaches, with silverweed (Argentina anserina), sometimes with beach heather (Hudsonia tomentosa) .................................... Lakeshore Beach (Provisional) (p. 232) 7. Shoreline outcrops, mostly along rivers, with sparse forb-dominated vegetation; bluebell (Campanula rotundifolia), three-toothed cinquefoil (Sibbaldiopsis tridentata), tufted hairgrass (Deschampsia cespitosa) characteristic; substrate typically vertically fissured slaty or shaly rock (Note: for steep cliff faces, along streams and gorges, see couplet #22, these are usually on granitic rock as compared to vertically fissured slate)....................................... .............................................Bluebell - Balsam Ragwort Shoreline Outcrop (p. 152) 8. Open talus slopes (talus slopes with tree cover will key here, as well as in Wooded Uplands key) ...........................................................................................................9 8. Substrate not talus .......................................................................................13 9. Vegetation dominated by carpets of heath shrubs, such as Labrador tea (Rhododendron groenlandicum), sheep laurel (Kalmia angustifolia), pale laurel (Kalmia polifolia), over Sphagnum mosses and/or reindeer lichens, with scattered conifers ...............................10 9. Vegetation sparse, conditions more xeric .............................................................11 10. Vegetation cover nearly continuous over the talus, with Sphagnum dominating the bryoid layer; wetland vegetation in an upland subalpine setting, near treeline ..........................................................Heath - Lichen Subalpine Slope Bog (p. 172) 10. Vegetation very patchy, much exposed talus; bryoid layer has reindeer lichens (Cladina and Cladonia spp.) more extensive than Sphagnum cover; usually at lower elevations, though in cool microsites (type may be partially forested, primarily with spruce, or open) ........................................................Labrador Tea Talus Dwarf-shrubland (p. 134) 11. Sparsely vegetated patches in partially forested talus, trees primarily coniferous ...........................................................................Spruce Talus Woodland (p. 58) 11. Sparsely vegetated patches in partially forested talus, trees primarily deciduous................12 12. Ironwood, sugar maple, and/or basswood present in the tree layer; open spots with enriched site indicators e.g. round-leaved dogwood (Cornus rugosa), herb Robert (Geranium robertianum), hepatica (Hepatica nobilis var. obtusa), columbine (Aquilegia canadensis), blue-stem goldenrod (Solidago caesia), wide-leaved sedge (Carex platyphylla). ..............................................................Ironwood - Oak - Ash Woodland (p. 84) 12. Paper birch, yellow birch, and/or red oak are the major trees; enriched site indicators absent or very incidental............................................Birch - Oak Talus Woodland (p. 82) 13. Substrate sandy outwash; flat or rolling plains with lowbush blueberry (Vaccinium angustifolium) and/or velvet-leaf blueberry (V. myrtilloides) among the dominant plants...14 13. Substrate rocky; mountains or hills ................................................................15 14. Blueberry (mostly lowbush blueberry) growing with little bluestem (Schizachyrium scoparium), other grasses, forbs, and occasional pitch pine; southern Maine ..........................................Little Bluestem - Blueberry Sandplain Grassland (p. 144) 14. Blueberry (mostly lowbush blueberry) growing among extensive carpets of reindeer lichens (Cladina and Cladonia spp.); pitch pine absent; spruces, red pine, or white pine may be scattered; downeast and extreme northwestern Maine .....................................................................Blueberry - Lichen Barren (p. 126) 15. Alpine areas: rocky summits and slopes near or above treeline, usually >3500' elevation; if tree species present, then less than 2 m tall; vegetation may be patchy or more continuous ................................................................................................................16 15. Open areas with patchy vegetation on hills or low mountains, below treeline; scattered trees often present ................................................................................................22 16. Vegetation dense masses or patches of stunted conifers, mostly 1 - 2 meters tall, forming a band between treeline and more open summit areas ..............................................................Spruce - Fir - Birch Krummholz (p. 116) 16. Vegetation not krummholz ...........................................................................17 17. Vegetation dominated by deciduous non-heath shrubs > 0.5 m tall; shrublands on subalpine tablelands or somewhat protected slopes between treeline and the dwarf - heath alpine zone, sometimes around subalpine pondshores; dominants include mountain alder (Alnus viridis ssp. crispa), bush-honeysuckle (Diervilla lonicera) and meadowsweet (Spiraea alba).........................Mountain Alder - Bush-honeysuckle Subalpine Meadow (p. 120) 17. Vegetation mixed dwarf shrubs and herbs; shrubs mostly < 0.5 m tall, often < 0.2 m tall, forming low mats, and primarily heath shrub speciesl subalpine to alpine elevations ..............................................................................................................18 18. Alpine bilberry (Vaccinium uliginosum) and crowberry (Empetrum nigrum, E. atropurpureum) common, highland rush (Juncus trifidus) often present, strictly alpine species (see list in next half of couplet) absent; patches of vegetation over bare rock, usually below or near treeline, but may extend higher ..................................Crowberry - Bilberry Summit Bald (p. 122) 18. One or more strictly alpine species present (not necessarily dominant): diapensia (Diapensia lapponica), boreal bentgrass (Agrostis mertensii), Bigelow's sedge (Carex bigelowii), alpine bearberry (Arctostaphylos alpine), Lapland rosebay (Rhododendron lapponicum), bearberry willow (Salix uva-ursi), tundra dwarf birch (Betula glandulosa), moss plant (Harrimanella hypnoides), mountain heath (Phyllodoce caerulea), star saxifrage (Saxifraga foliolosa) or alpine bistort (Persicaria vivipara).....................................................19 19. Herb-dominated cliffs and narrow benches on steep slopes (typically cirque walls), with constant seepage; rare alpine/boreal plants such as star saxifrage (Saxifraga foliolosa), alpine bistort (Persicaria vivipara), hairy arnica (Arnica lanceolata), and/or northern painted cup (Castilleja septentrionalis) typically present though not abundant ........................................................................................Alpine Cliff (p. 138) 19. Vegetation primarily dwarf shrubs; not on seepy cirque walls .....................................20 20. Protected areas where snow lingers, such as at summit edge, upper slopes, or base of cliffs; alpine bilberry (Vaccinium uliginosum) typically dominant and mountain-heath (Phyllodoce caerulea), tundra dwarf birch (Betula glandulosa), or moss-plant (Harrimanella hypnoides) characteristic .............................. Bilberry - Mountain-heath Alpine Snowbank (p. 132) 20. More exposed areas; alpine bilberry may be prominent but mountain-heath, tundra dwarf birch, and moss-plant absent .....................................................................................21 21. Cushions of diapensia (Diapensia lapponica) dominate vegetation (>30% cover, or >40% relative cover), with alpine bilberry; herbs <10% cover...Diapensia Alpine Ridge (p. 130) 21. Diapensia if present is not dominant; vegetation a variable mixture of dwarf evergreen shrubs and herbs, with graminoid cover (especially Bigelow's sedge, Carex bigelowii) locally extensive..........................................Dwarf Heath - Graminoid Alpine Ridge (p. 124) 22. Sparsely vegetated, nearly vertical rock faces ........................................................23 22. Summits or upper slopes, more extensive and not cliffs ...........................................24 23. Sparsely vegetated circumneutral rock faces, usually small in area; composition variable but includes some species indicative of higher pH, such as shrubby cinquefoil (Pentaphylloides floribunda), ebony sedge (Carex eburnea), rock whitlow-cress (Draba arabisans), lance-leaved draba (D. lanceolata), Laurentide primrose (Primula laurentiana), smooth woodsia (Woodsia glabella), etc............................Boreal Circumneutral Open Outcrop (p. 142) 23. Cliff faces with sparse vegetation and without circumneutral indicator species; granitic or other acidic bedrock.............................................................Acidic Cliff - Gorge (p. 150) 24. Vegetation a mosaic of tree or tall shrub islands within the predominant heath shrub cover; tree cover 5-25%; tall shrub and stunted tree patches form 10% - 70% cover and typically include mountain holly (Nemopanthus mucronata); at moderate elevations (usually > 2000') inland, or at lower elevations near the coast ......................Subalpine Heath - Krummholz (p. 128) 24. Patches of heath shrubs and herbs over bare rock, almost all under 0.5 m tall, with shrub and tree cover (>1 m tall) <10%..................................................................................25 25. Bald summits or upper slopes of inland hills or mountains, > 1800', with patchy vegetation dominated by crowberry (Empetrum nigrum or E. earnesii) and/or alpine bilberry (Vaccinium uliginosum); herbs, other than three-toothed cinquefoil (Sibbaldiopsis tridentata), are subalpine species such as highland rush (Juncus trifidus), mountain sandwort (Minuartia groenlandica) or dwarf rattlesnake root (Prenanthes nana) .........................................................Crowberry - Bilberry Summit Bald (p. 122) 25. Bald summits, mostly near the coast, without crowberry and bilberry (broom-crowberry, Corema conradii, may be present); a mixture of dwarf shrubs and herbs, including lower-elevation species such as common hairgrass (Deschampsia flexuosa), Rand's goldenrod (Solidago simplex var. randii), pinweed (Lechea intermedia), orange-grass (Hypericum gentianoides), or smooth sandwort (Minuartia glabra) .....................................Three-toothed Cinquefoil - Blueberry Low Summit Bald (p. 140) OPEN WETLANDS KEY 1. Tidal wetlands ..........................................................................................2 1. Non-tidal wetlands .........................................................................................6 2. Saltmarshes: vegetation varies, saltmeadow cordgrass (Spartina patens) and/or smooth cordgrass (S. alterniflora) present and often a major component; dominants also may include black-grass (Juncus gerardii), 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 (Plantago maritima) that may be extensive beneath the graminoids) ................................................................................Spartina Saltmarsh (p. 206) 3. Saltmarsh cordgrasses and/or black-grass are not strongly dominant, "canopy" vegetation more a mixture of graminoids and forbs; chair-maker's rush (Schoenoplectus pungens) typically present, and may be dominant.......Mixed Graminoid - Forb Saltmarsh (p. 208) 4. Shrubs dominate.........................Willow - Alder Tidal Shrubland (Provisional) (p. 232) 4. Herbaceous plants dominate .............................................................................5 5. Brackish tidal setting; vegetation a mix of tall graminoids and rosette-forming forbs; freshwater cordgrass (Spartina pectinata) and/or wire rush (Juncus arcticus) usually present; obligate freshwater species such as cardinal flower (Lobelia cardinalis), sweet flag (Acorus calamus), and pickerelweed (Pontederia cordata) absent .....................................................................Brackish Tidal Marsh (p. 210) 5. Freshwater, near the upstream end of the tidal reach; vegetation graminoid-dominated, with wild rice (Zizania spp.) and/or softstem bulrush (Schoenoplectus tabernaemontanii) typical; some obligate freshwater plants such as pickerelweed, cardinal flower, and/or sweet flag present.............................................................Freshwater Tidal Marsh (p. 212) 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; 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 dominate ...................................................................8 7. Plants with floating or submerged leaves dominate ................................................10 8. Pickerelweed (Pontederia cordata) dominant among the emergent species ................. ....................................................Pickerelweed - Macrophyte Aquatic Bed (p. 182) 8. Graminoids dominant among emergent species .......................................................9 9. Bulrushes (Schoenoplectus spp.) and/or bayonet rush (Juncus militaris) dominant .........................................................................................Bulrush Bed (p. 188) 9. Cattails (Typha spp.) dominant ................................................Cattail Marsh (p. 190) 10. Some plants indicative of higher pH waters present, e.g. tapegrass (Vallisnerai americana), common waterweed (Elodea canadensis), water stargrass (Zosterella dubia), white water crowfoot (Ranunculus aquatilis), Robbins' pondweed (Potamogeton robbinsii), alpine pondweed (P. filiformis var. alpinus), Vasey's pondweed (P. vaseyi), and straight-leaved pondweed (P. strictifolius); water-shield (Brasenia schreberi), pipewort (Eriocaulon aquaticum), water lobelia (Lobelia dortmanna), and pickerelweed (Pontederia cordata) absent or virtually so..........Circumneutral - Alkaline Water Macrophyte Suite (p. 135) 10. Alkaline indicators absent; vegetation usually includes pipewort, water lobelia, pondweed species other than those listed above, and/or water-lilies (Nymphaea variegata and Nuphar spp.) ................................................................................................................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 (p. 214) 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 (p. 216) 12. Gently-sloping pondshores (usually of small ponds in sandy outwash) where natural water levels usually drop by late summer, exposing progressive bands of vegetation: a band of shrubs at the upland/pondshore edge, then three-way sedge (Dulichium arundinaceum) or bayonet rush (Juncus militaris), and usually narrow-leaved goldenrod (Solidago tenuifolia), dominant in the upper shore zone, then pipewort (Eriocaulon aquaticum) or other more aquatic species in the most long-flooded zone; golden pert (Gratiola aurea) and meadow beauty (Rhexia virginica) usually present as indicators (see couplet 22 for herbaceous lakeshore vegetation that is not in distinct bands) ...Three-way Sedge - Goldenrod Outwash Plain Pondshore (p. 176) 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 (p. 174) 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 (p. 172) 15. Vegetation of lakeshores or large (third-order or higher) rivershores, 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 smaller stream drainages, with organic soils or with an organic layer over mineral substrate; vegetation often covering a large part of the basin; saturated through all or most of the year .......................................................................23 16. Shrubs, mostly >1 m tall, dominate ..................................................................17 16. Shrubs < 1 m tall, or mixture of shrubs and herbaceous plants, dominate ......................18 17. Dogwood (Cornus spp.) and willows (Salix spp.) predominate, alders often present .......................................................Dogwood - Willow Shoreline Thicket (p. 156) 17. Heath shrubs predominate.......Blueberry - Heath Shoreline Thicket (Provisional) (p. 232) 18. 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 (Parnassia glauca), Kalm's lobelia (Lobelia kalmii), sticky false asphodel (Tofieldia glutinosa); bryophyte layer at least locally well developed, with species other than Sphagnum dominant..............................................Circumneutral Riverside Seep (p. 178) 18. Vegetation of almost-flat rivershore or lakeshore beaches, substrate gravelly to sandy and not constantly saturated to the surface by seepage; bryophytes sparse or absent..............19 19. Tall graminoids and forbs dominant, forming a dense meadow; shrubs, if present, are rarely taller than the herbs; bluejoint (Calamagrostis canadensis), spotted joe-pye weed (Eupatorium maculatum), and flat-topped white aster (Doellingeria umbellata) characteristic ................................................................................Bluejoint Meadow (p. 184) 19. Vegetation more sparse and not dominated by bluejoint ..........................................20 20. On rivershores ...........................................................................................21 20. On lakeshores or pondshores ............................................................................22 21. Beach heather (Hudsonia tomentosa) a locally prominent dwarf shrub; islands of gray birch usually present; little bluestem (Schizachyrium scoparium) one of the more common graminoids; documented in Maine only from Saco River drainage ...........................................................................Hudsonia River Beach (p. 164) 21. Sand cherry and roses the dominant dwarf shrubs, beach heather absent; tufted hairgrass (Deschampsia cespitosa) characteristic; little bluestem absent; Laurentian/Cordilleran plants such as Huron tansy (Tanacetum bipinnatum), alpine sweet broom (Hedysarum alpinum), and alpine milk-vetch (Astragalus alpinus) often present; in Maine documented only on far northern rivers.............................Sand Cherry - Tufted Hairgrass River Beach (p. 180) 22. Sparse vegetation on lakeshore cobble or sand beaches; silverweed (Argentina anserina) typical, beach heather (Hudsonia tomentosa), or golden heather (Hudsonia ericoides) may be present.......................................................Lakeshore Beach (Provisional) (p. 232) 22. Patchy or sparse vegetation on subalpine gravelly pondshores ........................ .............Mountain Alder - Bush-honeysuckle Subalpine Meadow (p. 120) (pondshore variant) 23. 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 .................................................................................................24 23. 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 .....................................................36 24. Alpine or subalpine basin peatlands, near or above treeline ...............................................................Cotton-grass - Heath Alpine Bog (p. 204) 24. Lower elevation wetlands .............................................................................25 25. Bryophyte-dominated, often in raised peatlands; substrate wet and unstable; vascular plants usually <25% cover and limited to low-growing species e.g. cranberries (Vaccinium oxycoccos, V. macrocarpon), horned bladderwort (Utricularia cornuta), and white beak-rush (Rhynchospora alba); very dwarfed leatherleaf (Chamaedaphne calyculata) or other ericads may be present ...............................................................Bog Moss Lawn (p. 220) 25. Shrub and/or herb cover more extensive; vegetation not primarily bryophytes...................26 26. Shrub cover, including dwarf shrubs, exceeds graminoid cover ...................................27 26. Graminoid cover equals or exceeds shrub cover, including dwarf shrubs .......................32 27. Vegetation dominated by tall shrubs (mostly > 1.5 m); mountain holly (Nemopanthus mucronata), alder, and wild calla (Calla palustris) characteristic; standing water usually present among hummocks of Sphagnum; in peatlands often at the upland/peatland interface ...................................................Mountain Holly - Alder Woodland Fen (p. 162) 27. 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 ..........................28 28. Shrubby cinquefoil (Pentaphylloides floribunda) a prominent shrub, and other circumneutral indicators present, e.g. livid sedge (Carex livida), grass-of-Parnassus (Parnassia glauca), and/or Kalm's lobelia (Lobelia kalmii) ....................................... ...........Shrubby Cinquefoil - Sedge Circumneutral Fen (p. 200) (shrubby expression of this type) 28. Shrubby cinquefoil absent (or scarce) and other circumneutral indicators lacking...............29 29. Shrubs relatively tall (often >1 m) with sweetgale (Myrica gale), hardhack (Spiraea tomentosa), and/or meadowsweet (Spiraea alba) prominent; leatherleaf (Chamaedaphne calyculata) often present but other ericads not abundant; typically in standing shallow water without a continuous Sphagnum carpet.........Sweetgale Mixed Shrub Fen (p. 158) 29. Vegetation dominated by ericads (though sweetgale often present), usually well under 1 m tall; bogs and fens on well developed Sphagnum carpets .............................................30 30. Low bog vegetation with dwarf huckleberry (Gaylussacia dumosa) locally dominant (often patchy), >20% cover; black crowberry (Empetrum nigrum) and/or deer-hair sedge (Trichophorum cespitosum) 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 (p. 170) 30. Other shrubs dominant, or if dwarf huckleberry dominant then neither black crowberry nor deer-hair sedge present; both coastal and inland ...................................................31 31. 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 (p. 168) 31. Ombrotrophic bog conditions (vegetation mostly raised above the water table), with sheep laurel (Kalmia angustifolia), Labrador tea (Rhododendron groenlandicum), and/or rhodora (Rhododendron canadense) together more abundant than leatherleaf and sweetgale; graminoid cover rarely exceeds 15%.................Sheep Laurel Dwarf Shrub Bog (p. 166) 32. Sedge-dominated lawns, deer-hair sedge (Trichophorum cespitosum) and/or coast sedge (Carex exilis) characteristic; centrally located on raised (ombrotrophic) plateau bogs within about ten miles of the coast, Hancock County east...Deer-hair Sedge Bog Lawn (p. 202) 32. Fen (minerotrophic) setting, areas sometimes transitional to bogs, but not the central lawn of a coastal plateau bog ........................................................................................33 33. Fens with circumneutral indicators e.g. livid sedge (Carex livida), yellow sedge (C. flava), grass-of-Parnassus (Parnassia glauca), Kalm's lobelia (Lobelia kalmii), and/or shrubby cinquefoil (Pentaphylloides floribunda), usually with more than one indicator species ...........................................Shrubby Cinquefoil - Sedge Circumneutral Fen (p. 200) 33. Circumneutral indicator species absent or virtually so ...............................................34 34. Vegetation dominated by tall sedges: dominant species are slender sedge (Carex lasiocarpa), beaked sedge (C. utriculata), and/or lake bank sedge (C. lacustris); or rarely tussock sedge (C. stricta) or inflated sedge (C. vesicaria)....Mixed Tall Sedge Fen (p. 196) 34. Slender sedge, beaked sedge, lake bank sedge, and inflated sedge not the dominant sedges, vegetation mostly lower .................................................................................35 35. Carpets of low sedges over very wet Sphagnum substrate, with mud sedge (Carex limosa), podgrass (Scheuchzeria palustris) and white beak-rush (Rhynchospora alba) characteristic; dwarf or creeping shrubs may be mixed with the sedges but are sparse (<20% cover) ..............................................................Low Sedge - Buckbean Fen Lawn (p. 198) 35. 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 (Carex oligosperma), coast sedge (C. exilis), Michaux's sedge (C. michauxii), white beak-rush, and/or narrow-leaved cotton-grass (Eriophorum angustifolium) ..................................................................Sedge - Leatherleaf Fen Lawn (p. 194) 36. Tussock sedge (Carex stricta) 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 (p. 192) 36. Herb component dominated by species other than tussock sedge ..................................37 37. Shrub cover exceeds herb cover ........................................................................38 37. Herb cover exceeds shrub cover ........................................................................40 38. Mixture of herbs and shrubs; dominant shrubs are not alder, sweetgale (Myrica gale), or ericads, but are more often buttonbush (Cephalanthus occidentalis) or bog willow (Salix pedicellaris) ..................................Mixed Graminoid - Shrub Marsh (p. 186) (shrubby expression of this usually herbaceous or mixed type) 38. Alder, sweetgale, and/or ericads are the dominant shrubs ...........................................39 39. Alders strongly dominant, >20% cover; ericads absent or virtually so ..............................................................................Alder Shrub Thicket (p. 160) 39. Sweetgale and/or heath shrubs dominant, alders clearly subordinate .....................................................................Sweetgale Mixed Shrub Fen (p. 158) 40. Bluejoint (Calamagrostis canadensis) dominates herb component, >50% cover; shrubs <25% cover ........................................................................Bluejoint Meadow (p. 184) 40. Mixture of herbs and shrubs (herbs 25-95%, shrubs 0-70% cover), without dominance of tussock sedge (Carex stricta), bluejoint (Calamagrostis canadensis), or alder ............................................................Mixed Graminoid - Shrub Marsh (p. 186) 1 In this document, "deciduous trees" does not include larch, our only deciduous conifer. "Broad-leaf trees" would be a more accurate term, but "deciduous" is far more widely used. 2 Relative Dominance: the percent of the canopy (or basal area) made up of that species. Explained further in the Definitions section. 3 Vascular plant nomenclature follows Flora of Maine (Haines and Vining 1998); scientific names are given for most shrubs and herbs, and not for trees (for which common names are more widely known). See Appendices for name cross-references.