Betula populifolia multiple trunks branching off of an old stump. The leaves are 5-7.5 cm long by 4–6 cm wide, alternately arranged, ovate, and tapering to an elongated tip. They are dark green and glabrous above and paler below, with a coarsely serrated margin. The bark is chalky to grayish white with black triangular patches where branch meets trunk. It is most easily confused for the paper birch ("Betula papyrifera") by means of its bark; it is smooth and thin but does not readily exfoliate like paper birch does. The flowers are wind-pollinated catkins 5–8 cm long, the male catkins pendulous and
Northern celestial hemisphere Northern celestial hemisphere The northern celestial hemisphere, also called the Northern Sky, is the northern half of the celestial sphere; that is, it lies north of the celestial equator. This arbitrary sphere appears to rotate westward around a polar axis due to Earth's rotation. At any given time, the entire Northern Sky is visible from the geographic North Pole, while less of this hemisphere is visible the further south the observer is located. The southern counterpart is the southern celestial hemisphere. In the context of astronomical discussions or writing about celestial cartography, this celestial hemisphere may also simply then be