Brewer's spruce is a large
evergreen conifer growing to tall, exceptionally 54 m, and with a trunk diameter of up to 1.5 m. The
bark is thin and scaly, and purple-gray in color. The crown is very distinct, distinguished by level branches with vertically pendulous branchlets up to , each branch forming a 'curtain' of foliage. The pendulous foliage only develops when the tree grows to about 1.5–2 m tall; young trees smaller than this (up to about 10–20 years old) are open-crowned with sparse, level branchlets. The shoots are orange-brown, with dense short pubescence about 0.2 millimeters long and very rough with
pulvini 1–2 mm long. The
leaves are borne singly on the pulvini, and are needle-like but with a blunt tip, 15–35 mm long, flattened in cross-section, glossy dark green above, and with two bands of white
stomata below. The
cones are longer than most other North American spruces, pendulous, cylindrical, long and 2 cm broad when closed, opening to 3–4 cm broad. They have smoothly rounded, thin, flexible scales 2 cm long. The immature cones are dark purple, maturing red-brown 5–7 months after pollination. The
seeds are black, 3–4 mm long, with a slender, 12–18 mm long pale brown wing. == Genetics ==