Taxus brevifolia

Taxus brevifolia, called the Pacific yew or western yew, belongs to the yew family Taxaceae and is native to the Pacific Northwest of North America. This small evergreen conifer, which can also appear as a shrub, does best in moist conditions. It grows very slowly and often rots from the inside, creating hollow trunks that make it hard—sometimes impossible—to determine a tree’s true age by counting rings. Forest succession frequently damages it, leaving it with a squat, multi-leader form that can sprout anew from cut stumps. In its shrubby state, sometimes called “yew brush,” it can reproduce vegetatively through layering.

The bark is thin and scaly, starting red and turning purplish-brown, covering a thin layer of off-white sapwood and a darker heartwood that ranges from brown to purplish to deep red, or even bright orange when freshly cut. The leaves are lanceolate, flat, and dark green, arranged spirally on the stem but twisted at the base so they lie in two flat rows on either side of the stem, except on erect leading shoots where the spiral is more obvious.

Seed cones are highly modified: each contains a single seed partly surrounded by a scale that becomes a soft, bright red, berry-like aril, open at the end. Arils mature six to nine months after pollination. Thrushes and other birds eat the arils and disperse the hard seeds undamaged in their droppings; aril maturation is spread over two to three months to improve seed dispersal. Male cones are globose and shed pollen in early spring. The species is mostly dioecious, but occasional individuals can be variably monoecious or change sex over time.

Two varieties are recognized. *Taxus brevifolia* var. *reptaneta*, or thicket yew, is a shrub that generally occurs at mid to upper elevations of the typical variety’s range, at its southernmost in the Klamath Mountains and at lower elevations further north. Its stems creep along the ground before curving upward, with branches mostly on the upper side. The name *reptaneta* comes from Latin *reptans*, meaning “creeping, prostrate, and rooting,” and *-etum*, meaning “collective place of growth,” referring to the yew thickets it forms. Unlike the typical variety, thicket yew grows abundantly on open sunny avalanche shoots, ravines, and forest margins. In northwestern Montana, a variant stays prostrate along the ground, likely the ancestral form. Some botanists consider *reptaneta* synonymous with the typical variety, using it only to describe different geographical ranges, though the two may be genetically distinct. It has also been proposed as a subspecies.

*Taxus brevifolia* var. *polychaeta*, or worm cone yew, differs from the typical variety by producing a longer primary shoot with up to five secondary shoots, resembling a polychaete worm. It is relatively rare and may have been extirpated from its type locality near Mud Bay, Olympia, Washington, due to urban expansion. It is also known from northern Idaho and Sonoma County, California. As with thicket yew, some reports consider worm cone yew the same as the typical variety, but no specific studies support this. The authority describing both varieties had studied *Taxus* for 25 years at the time.

Yew foliage closely resembles that of *Sequoia sempervirens*, the coastal redwood.

Pacific yew ranges from southernmost Alaska south to northern California, mostly in the Pacific Coast Ranges, with isolated populations in southeast British Columbia and northern Idaho. It grows in various environments but is limited to streamside habitats in drier areas; in moist environments, it occurs on slopes and ridgetops up to high elevations. It is shade tolerant but can also grow in sun.