Many workers have been interested in creating a quantitative means to determine ecosystem type from aspects of leaf form. We performed eigenshape analysis of leaf outlines for two extant and two fossil assemblages. For both the extant and fossil flora, one assemblage represented leaves from tropical areas and one from temperate. The data for the extant assemblages suggests that temperate assemblages occupy a larger region of morphospace. This holds true for the first twenty eigenshape axes examined. Eigenshape axis 2 appears to represent the length to width ratio; the tropical leaves are clustered from an average leaf shape to one with a high length to width ratio, while the temperate leaves are scattered across the entire axis. Eigenshape axis 3 appears to show variation due to an elongate tip or petiole; on this axis, the tropical leaves are clustered near the average leaf shape. This distribution may reflect the very long petioles on some temperate leaves; however, it seems to contradict the expectation that tropical leaves will display longer drip tips. The combined data for all assemblages agrees with the taxonomic determination of ecosystem type for the fossil assemblages. The temperate fossil flora occupies a greater region of morphospace, while the fossil rainforest flora falls within the morphospace of the extant tropical flora. The implications of our findings in understanding fossil assemblages will be discussed, and the broader questions of paleoclimate determination will be considered.

Key words: climate, ecosystem, fossil assemblage, leaf form, morphometrics