Physiognomy and Structure: This group contains a moss peat layer with depths exceeding 40 cm. Dwarf-shrubs and thin-leaved graminoids are >25%, and trees <25%. There is a discontinuous to absent layer of Sphagnum peatmoss (<80% cover), with brown mosses present to dominant. Ericaceous dwarf-shrubs are typically minor, with broad-leaved shrubs dominant. Broad-leaved non-ericaceous shrubs exceed cover of ericaceous shrubs (>50%), although some shore fens may be more ericaceous-dominated. Thin-leaved graminoids are common. The tree layer is rare to absent (though some treed fens may fall within this group).

The landscape morphology of alkaline peatlands is often very striking. A variety of approaches has been taken to describe these forms: in Maine, see Davis and Anderson (2001); in Canada, see National Wetlands Working Group (1988); and in Minnesota, see Glaser (1992a). In Canada, bog and fen peatlands each have their own set of forms. In Minnesota, Glaser treats bogs and fens together as part of larger patterned peatland complexes (mire complexes). Particularly distinctive are the ribbed bogs or fens in which a pattern of narrow (2- to 3-m wide), low (<1 m deep) ridges are oriented at right angles to the direction of the drainage (National Wetlands Working Group 1988). Wet pools or depressions occur between the ridges. These patterned peatlands may include string bog, Atlantic ribbed fen, or northern ribbed fen (National Wetlands Working Group 1988). They develop almost entirely north of 46°N latitude in east-central Canada and the adjacent U.S. They are minerotrophic peatlands in which the vegetation has developed into a pattern of strings (raised, usually linear features) and flarks (wet depressions separating the strings). The substrate chemistry is entirely acidic in some peatlands; in others, where bedrock or other substrate influence creates circumneutral to calcareous conditions, peatland chemistry may be entirely calcareous or vary from acidic to calcareous within the same peatland. In acidic portions, typical bog heaths predominate mixed with sedges. Dasiphora fruticosa ssp. floribunda is diagnostic of circumneutral to calcareous conditions. These peatlands usually develop in open basins and flat plains, and the patterned portion may occupy only a fraction of the entire peatland. The edge of the basin may be shallow to deep peat over a sloping substrate, where seepage waters provide nutrients.

Floristics: This group contains a moss peat with depths exceeding 40 cm. Dwarf-shrubs and thin-leaved graminoids are >25%, and trees <25%. There is a discontinuous to absent layer of Sphagnum peatmoss, with brown mosses (Calliergon, Campylium, Drepanocladus, Tomentypnum) present to dominant. Ericaceous dwarf-shrubs (especially Chamaedaphne calyculata but occasionally Andromeda polifolia, Kalmia polifolia, Vaccinium oxycoccos) may be common to minimal, with broad-leaved shrubs (Alnus incana, Betula glandulosa, Betula michauxii, Betula pumila, Dasiphora fruticosa ssp. floribunda, Myrica gale, Salix spp.) minor to dominant. Thin-leaved graminoids include Carex interior, Carex lasiocarpa, Carex limosa, Carex livida, Eriophorum viridicarinatum, Muhlenbergia glomerata, Rhynchospora alba, and Trichophorum alpinum. Mosses include Aulacomnium palustre, Campylium stellatum, Limprichtia revolvens (= Drepanocladus revolvens), Pleurozium schreberi, Scorpidium scorpioides, Sphagnum angustifolium, Sphagnum capillifolium, Sphagnum magellanicum, and Tomentypnum nitens (Harris et al. 1996, Minnesota DNR 2003).

Dynamics:  No Data Available