Taxus baccata Yew

Yew is one of only three conifer species that are native in the British Flora. Individual trees are either males or females (i.e it is dioecious), with males producing small cones, solitary or in short spikes, early in the spring. Pollen from the male cones fertilises the small female cones which then go on to produce a fleshy aril (erroneously referred to as a berry) which contains a single seed. The fleshy part of the aril is edible and sweet but the seed, which contains toxic alkaloids, is poisonous. The arils are consumed by various frugiverous birds such as thrushes who discard the poisonous seed. This affords an effective dispersal mechanism and, consequently, naturalised yews are common. Some birds, notably the Hawfinch are able to consume the toxic seeds with impunity. Yews grow rather slowly, some for more than 1,000 years, to a height of 20m or more with girths of up to 10m in circumference. Yew trees are difficult to age with accuracy, but some trees in Britain may be as much as 3,000 years old and the yew tree in St Cynog's churchyard in Defynog could be 5,000 years old, making it the oldest plant in Britain. . It is an iconic tree steeped in pagan, Christain and folk lore traditions and used by the Physicians of Myddfau. Many ancient trees are found in churchyards with some notable veterans (more than 500 years old) found in St John Baptist church in Glyncorrwg. Yews contains an array of bioactive phytochemicals, many of which are highly toxic, and which are used in treatments of various clinical conditions. The most significant are taxols and taxines which are important in cancer therapy and paclitaxel (taxol) in particular which is used as a potent anti-cancer drug in chemotherapy. In Agatha Christie's novel 'A pocket full of rye', which is set in fictitious Yewtree Lodge, one of the murders is the result of taxine poisoning. Although Yew is undoubtedly native on wooded limestone cliffs in Wales (e.g. Carreg Cennen in Dyfed) there is little evidence that it is native in West Glamorgan. However, the status of some old trees that occur on the slopes of the south Gower limestone cliffs is interesting and may warrant investigation.

Neophyte