ワタスゲ
"Carex bigelowii" grows in many types of Arctic and alpine habitat. It occurs in forest, bog, meadows and tundra. It occurs alongside plants such as willows ("Salix" spp.), dwarf arctic birch ("Betula nana"), lingonberry ("Vaccinium vitis-idaea"), bog blueberry ("V. uliginosum"), crowberry ("Empetrum nigrum"), northern Labrador tea ("Ledum palustre"), American green alder ("Alnus crispa"), cloudberry ("Rubus chamaemorus"), alpine bearberry ("Arctostaphylos alpina"), varileaf cinquefoil ("Potentilla diversifolia"), elephanthead lousewort ("Pedicularis groenlandica"), white mountain avens ("Dryas octopetala"), entireleaf mountain avens ("D. integrifolia"), alpine timothy ("Phleum alpinum"), alpine rush ("Juncus alpinoarticulatus") and tussock cottongrass ("Eriophorum vaginatum"), as well as feathermosses ("Hylocomium" and "Aulacomium" spp.), lichens ("Cladonia" and "Cladina" spp.), and sphagnum mosses. In Scotland, particularly on Glas Maol, this sedge is codominant with the moss "Racomitrium lanuginosum" in a heath ecosystem, the British NVC community U10. The sedge is also associated with this moss on lava fields in Iceland.