Betula spp.; birch [Betulaceae]  Deciduous trees with peeling bark and simple, doubly-toothed, deciduous leaves that tend to occur in pairs on scarcely noticeable reduced side branches.  Staminate flowers occur in catkins that form in the fall and produce pollen early in the spring.  Pistillate flowers occur in almost conelike clusters, and produce large numbers of tiny (¼“) winged seeds.  Ten species are found in our flora, with 3 being most common.  B. papyrifera (paper birch), with its well-known white bark, is fast-growing, but short-lived.  B. alleghaniensis (yellow birch) requires better soils, and can be a long-lived, massive tree.  B. nigra (river birch) is most common on wet sites.  [087]