Cornus nuttallii, the Pacific dogwood, western dogwood, or mountain dogwood, is a species of dogwood tree native to western North America. Description It is a small to medium-sized deciduous tree, reaching tall, often with a canopy spread of . Its habit varies based on the level of sunlight; in full sun it will have a short trunk with a crown as wide as it is tall, while under a canopy it will have a tapered trunk with a short, slender crown. The trunk attains in diameter. The bark is reddish brown. The branches have fine hairs and the young bark is thin and smooth, becoming scale-like with ridges as it ages. The leaves are opposite, simple, oval, long, and broad. They are green with stiff, appressed hairs on top, and hairier and lighter on the bottom. They turn orange to purplish in autumn. The flowers are individually small and inconspicuous, across, produced in a dense, rounded, greenish-white flower head in diameter; the 4–8 large white 'petals' are actually bracts, each bract long and broad, creating the appearance of a larger flower head. The flowers commonly bloom twice per season, once in the spring and again in late summer or early fall. The fruit is a compound pink-red or orange drupe about long, in clusters containing 20–40 drupelets, each of which contains two seeds. They appear in September or October. Similar species The eastern United States' Cornus florida (flowering dogwood) is similar in appearance and possibly in chemical composition. Cornus canadensis has similar blossoms but grows as a groundcover. Etymology In 1806, Meriwether Lewis noted that the species is similar in appearance to C. florida. However, when Scottish botanist David Douglas encountered C. nuttalli on his expedition to the Pacific Northwest in the 1820s, he mistook it for C. florida and did not send seeds back to England. English botanist Thomas Nuttall was the first to describe the species for science while staying at Fort Vancouver in the autumn of 1834. It was named nuttallii after him by his friend John James Audubon. The common names comes from that of Cornus sanguinea, the hard wood of which Northern Europeans used to make nails ("dags") during the medieval era. Distribution and habitat It occurs from the lowlands of southern British Columbia to the mountains of southern California. There exists an inland population in central Idaho, where it is considered critically imperiled. It