Northern red-backed vole northern forest and shrubland habitats. They occur in every major forest type in central Alaska. Plant species commonly found in areas occupied by northern red-backed voles include black spruce ("Picea mariana"), white spruce ("P. glauca"), quaking aspen ("Populus tremuloides"), paper birch ("Betula papyrifera"), alder ("Alnus" spp.), willow ("Salix" spp.), mountain cranberry ("Vaccinium vitis-idaea"), blueberry and bilberry ("Vaccinium" spp.), bunchberry ("Cornus canadensis"), and a variety of grasses and forbs. Important fungi, mosses and lichens include truffle ("Endogone fascilulata"), Schreber's moss ("Pleurozium schreberi"), mountain fern moss ("Hylocomium splendens"), sphagnum ("Sphagnum" spp.), and lichens ("Cladonia and Peltigera" spp.). The breeding season of northern
Plant cell quite elongated, and may divide transversely to give a septate appearance. The role of this cell type is to support the plant in axes still growing in length, and to confer flexibility and tensile strength on tissues. The primary wall lacks lignin that would make it tough and rigid, so this cell type provides what could be called plastic support – support that can hold a young stem or petiole into the air, but in cells that can be stretched as the cells around them elongate. Stretchable support (without elastic snap-back) is a good way to describe what collenchyma does.