Mittwoch, 19. Oktober 2011

Plant of the Day (October 19th, 2011) - Taxus baccata L.

Since the start of this blog, I want to show you a (in my opinion) very interesting tree. However, I waited, because the fruits of this tree are one of its most distinctive features. I'm speaking of Taxus baccata L. from the Taxeaceae family. I'm sure, that you know this plant. In English it's called “European Yew” or often simple “Yew”, while in Germany, we call it “Europäische Eibe”.

T. baccata - habitus (garden tree)

T. baccata is a medium high tree, which can reach heights until 20 metres (65.6 feet), but it can also grow as scrub or bush. The needles are flat and 2 millimetres broad. Their dorsal site is dark green with an emerging leaf-vein, while the ventral site is bright green. The species has a scaly, maroon bark

The species is dioecious with male and female individuals. The male flowers are very small, numerous and with between six and fourteen stames. The ripe pollen are very light and can be spread out by the wind.

T. baccata - (scaly) bark and needles
(note the leaf-vein on the dorsal site)

The female flowers, located at short shoots, are bigger but still very inconspicuous. They consists of scales with one fertile scale at the top of the flower. This scale will form the pollination drop to catch the pollen from the air. Flowering time is very early in the year (between February and March).

T. baccata - red arils

Although T. baccata is a conifer, it has no cones as ripe fruits. Instead, the species forms a small, hard nut, which is wrapped in a red, fleshy “coat”: the so called Aril or Arillus. Its function is the attraction of birds, which eat the sweet-tasting aril and swallow the nut. The nut will be excreted later by the birds. This form of distribution is called Ornithochory. Yeah, I know it sounds disgusting, but it's a very common method of spreading.

T. baccata - short shoots (note the red base)

The roots of this species lay in Middle Europe but it can also be found in Anatolia, the Mediterranean Areas, North Africa and even Scandinavia. It's very undemanding towards its growth conditions and can be found both at acidic and base-rich soils. T. baccata is also very tolerant towards shading.

T. baccata - aril & nut

Through the high content of Taxanes, all parts of T. baccata, except the aril, are highly toxic to humans and the most animals. However, this toxin are harmless to even-toed ungulates (Cows, Deer), which can eat all parts of the tree. As a result, wild yew forest are very rare, because young trees are often eaten by deer before they get a chance to become mature. Curiously, the Taxanes are toxic to odd-toed ungulates (Horses, Donkeys), so T. baccata was opposed by farmers, in order to protect their horses against the venoms. That is another reason why naturally stocks of this tree are very rare today. However, it has become a popular plant for gardens and hedges.

The wood of T. baccata is a heartwood with a dark core. It's very elastic and is used to build bows, some musical instruments or for carving.

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