Which of these hedging plants contains taxine?

If you are an Agatha Christie fan you may have come across taxine as the poison featured in her novel “A Pocket Full of Rye”. Taxine is a toxic alkaloid obtained from the Taxus species of plants, including “Taxus baccata” (English yew), and “Taxus canadensis” (Canadian yew).

The toxic nature of yew trees has been known for thousands of years. All the Taxus species contain taxine in every part of the plant except in the berries. Concentrations vary between species, leading to varying toxicities within the genus: the English Yew contains high taxine concentrations, which leads to a high toxicity. There are seasonal changes in the concentrations of taxine in yew plants, with the highest concentrations during the winter, and the lowest in the summer. The poison remains dangerous in dead plant matter.

Taxus species are found exclusively in temperate zones of the northern hemisphere. They all have distinctive leaves, which are needle-like, small, spirally arranged but twisted so they are two-ranked, and linear-lanceolate. They are also characterized by their ability to regenerate from stumps and roots.