|Taxus baccata (European Yew) shoot with
mature and immature cones
The arils are edible and sweet, but the seeds are dangerously poisonous. Unlike birds, the human stomach can break down the seed coat and release the taxanes into the body. This can have fatal results if yew 'berries' are eaten without removing the seeds first.
The seeds and leaves will kill cattle and horses, but deer can break down the poisons and will eat yew foliage freely. In the wild, deer browsing of yews is often so extensive that wild yew trees are restricted to cliffs and steep slopes inaccessible to deer. The foliage is also eaten by the larvae of some Lepidopteran insects including Willow Beauty.
Yews are slow growing and can be very long-lived, and reach heights of 1-40 m, with trunk diameters of up to 4 m. They have reddish bark, spear-shaped flat, dark-green leaves 1-4 cm long and 2-3 mm broad, arranged spirally on the stem, but with the leaf bases twisted to align the leaves in two flat rows either side of the stem.
The seed cones are highly modified, each cone containing a single seed 4-7 mm long partly surrounded by a modified scale which develops into a soft, bright red berry-like structure called an aril, 8-15 mm long and wide and open at the end.
All of the yews are very closely related to each other, and often described together as Taxus baccata.