to assess the patterns of phenotypic variation in cone and needle characters of jack pine relative to spatial, climatic and ecological data, collections were made from ten trees in each of 64 sites in northwestern ontario. nineteen cone and forty needle characters were measured on five cones and five needles per tree. climatic data from 27 canadian and 10 american weather stations in and surrounding the study area were interpolated, using a geographic information system, to produce weather data for each collection site. vegetation and soil data for each collection site were determined using the system developed by the ontario ministry of natural resources in the northwestern and north central regions for the forest ecosystem classification program. discriminant analysis indicated that the populations in the study areas formed a single group but were spatially organized into two groups, west and east, including the armstrong area, of lake nipigon. a trend surface of the discriminant scores revealed a steep dine at a longitude of 88°15', nipigon area. simple regression of discriminant scores against the spatial, climatic and ecological data indicated that the patterns of variation expressed by cone and needle characters may be a result of adaptation to local environments.(see document for elevations) multiple regression coefficients from regressions of spatial and climatic data against discriminant scores for both cone and needle data were compared with the variance component among groups from the nested analysis of variance to assess the amount of the total variation attributable to the local environment. the comparison revealed that most of the variation among sites could be explained by spatial and climatic data. in addition, a steep dine could be discerned at a longitude of 88°15’ on the the trend surface of maximum june temperature. the correlations of the patterns of variation with the spatial and climatic data suggest that climate may be the causal agent for the patterns of variation in cone and needle characters in northwestern ontario. however, the patterns of cone and needle characters are similar suggesting that the modern patterns of variation may be a result of two migration routes or two refugia.