Note 8 — SWEET BIRCH

The eastern species, which do not extend west of the continental divide, are, Sweet Birch (Betula lenta), Yellow Birch (Betula lutea), River Birch (Betula nigra), Paper Birch (Betula papyrifera), White Birch (Betula populifolia) and Blue Birch (Betula cærulea). The western birches, none of which are known to extend much east of the continental divide, are: Western Birch (Betula occidentalis), Mountain Birch (Betula fontinalis), White Alaska Birch (Betula alaskana), and Kenai Birch (Betula kenaica). The last two occur in Alaska, but not in United States proper.