The fossil record of conifers is characterized by fragmentary remains of simple organs with cryptic characters. There is also a wide range of variation from branch to branch on the same plant. Therefore, meaningful species delimitation is extremely difficult for many fossil confers, particularly Paleozoic conifers. Different authorities often assign the same specimen to different species, and the same authority may assign the same specimen to different species at different times. A large number of Upper Pennsylvanian conifer specimens from the 7-11 mine in Columbiana, Co., Ohio are preserved by a combination of coalified compression and pyrite permineralization. These specimens display features of external morphology, cuticular characters and internal anatomy, and can all be assigned to a single species with a high degree of confidence. The confident recognition of this single species allows us to record ranges of variation for a large number of characters, and to recognize differences that result from variables such as ontogeny, taphonomy, and/or different positions on the plant. Several multivariate methods have been employed to interpret similarities and differences resulting from each of these variables. Principal Component Analysis (PCA), Discriminant Function Analysis (DFA), and Cluster Analysis (CA) have been used to compare the features of different specimens. Individual specimens are best characterized by leaf length and width, angle of divergence, and diameter of vegetative shoots. Differences in these characters are correlated with shoot length and diameter. Angles of divergence in leaves seem to be a consistent feature among all the specimens. Such characters may explain differences among fossil conifer specimens due to biological or taphonomic variables, and they may be valuable for reliably distinguishing among species.

Key words: conifers, multivariate methods, Upper Pennsylvanian