Taxus canadensis has been generally recognized as a low shrub in NE North America. Its leaf papillae are confined to stomata bands, sometimes seen only along stomatal ridges. Stomata are mostly in 5-7 (-9) irregular rows/band with the higher counts from coastal and northern regions. These characteristics, and the elliptically shaped epidermal cells in leaf x-sections, indicate a closer affinity to yews of Europe than to other yews of North America. Three varieties are differentiated by arrangement of branchlets and leaves. Examples will be shown from different geographic regions. The typical variety, a low shrub that spreads by layering, has equally divided branchlets and two-ranked leaves. Similar specimens have been collected from shrubs and trees in Morocco, Madeira, France, Sweden, Estonia, Caucasus Mountains, and are evident in fossils described from Tertiary deposits in Europe. Their leaves differ slightly by more prominent papillae that often extend into the marginal zone; however, a fossil described by Z. Kvacek from a Miocene deposit in Bohemia is more similar to American than European plants. Variety minor, occasionally collected in North America and Madeira, differs by unequally divided branchlets with erect leaves. A third variety, based on T. baccata var. adpressa (= T. tardiva), is generally known in horticulture; however, wild forms are evident in specimens from Iowa (U.S.A.), Norway, Sweden, Slovenia, and a fossil from a Pliocene deposit in Bohemia. Other related plants include tree forms in Europe, Vietnam and Sichuan, and shrub forms in England, SE Russia, and Japan. Although shrub and tree forms of Taxus are often parapatric in E Asia and W North America, it would seem that the shrub form in E North America has survived more by vegetative reproduction, while the tree form has largely vanished.

Key words: leaf anatomy, paleobotany, phytogeography, taxonomic relationships of Taxus canadensis