Pollen analysts have always been haunted by the uncertainty of pollen representation proportionate to the forest complex they were to represent, and comparatively little work has been done on this important problem. Caroll investigated the problem in the Great Smoky Mountain area, Hansen in a western forest region, and Cain in 1953 began an extensive piece of work covering a wide geographical area. His plan was to associate moss polster pollen representation with basal area of trees in 1/10 to two acre plots. The present writers felt that such an approach does not well harmonize with the modus operandi in nature, when pollen settles out on the open surface of a lake or on a bog mat. They further felt that most of the plots (1/10 acre) were too small a unit on which to base the composite pollen rain of a given region, especially when the aim is to determine the over- and under-representation of certain genera. So it was planned to select a natural situation, i.e. an open bog mat and a more extensive analysis of the bordering forest, and to associate with such quadrat study pollen percentages obtained from moss polsters. The small Lac Shaw bog, one and a half miles south of the Mont Tremblant Biological Station, seemed ideally suited to such a study, especially since Potzger and Cortemanche had already presented a pollen profile from this bog.