Betula glandulosa to tall, often forming dense thickets. The trunks are slender, rarely over diameter, with smooth, dark brown bark. The leaves are nearly circular to oval, long and broad, with a toothed margin. The fruiting catkins are erect, long and broad. It is closely related to the dwarf birch ("Betula nana"), and is sometimes treated as a subspecies of it, as "B. nana" subsp. "glandulosa". It is distinguished from typical "B. nana" by the presence of glandular warts on the shoots and longer leaf petioles. Hybrids with several other birches occur. Betula glandulosa Betula glandulosa, the American dwarf birch, also known
Northern celestial hemisphere referred to as the Northern Hemisphere. For the purpose of celestial mapping, astronomers may conceive the sky as the inside of a sphere divided into two halves by the celestial equator. The Northern Sky or Northern Hemisphere is therefore the half of the celestial sphere that is north of the celestial equator. Even if this geocentric model is the ideal projection of the terrestrial equator onto the imaginary celestial sphere, the northern and southern celestial hemispheres is not to be confused with descriptions of the terrestrial hemispheres of Earth itself. Northern celestial hemisphere The northern celestial hemisphere, also called the