Saturday, 15 November 2014

Nature of Corsica 4: Trees and Shrubs

Umbrella Pine, Pinus pinea
With very little level ground for fields, most of northern Corsica that we saw is covered with forest and scrub.  Starting at the coast, on sunny hillsides can be found Euphorbia dendroides, Tree Spurge, the only non-herbaceous Euphorbia native to the mainland of Europe. It has a range around the Mediterranean, but because of its ornamental appearance it has been used in gardens in other parts of the world. As with many such plants, in some places it has “jumped the fence” and become an invasive weed in some places (California for example). This is especially a problem as like all Euphorbias it has a toxic latex and may cause dermatitis in people who come in contact with it

Euphorbia dendroides
From the coast up to a few hundred metres the island is dominated by maquis vegetation, a complex ecosystem of shrubs and sub-shrubs in which Tree Heather, Erica arborea, is prominent. In UK garden centres this is sold as a small shrub, but left to grow it can eventually reach 5m or more. The abundant flowers provide nectar for the production of honey, and important export of the island.

Erica arborea
Among the heather can also be found Strawberry Tree, Arbutus unedo. The specific name means “I eat one” – not because the fruit is poisonous but because it is almost tasteless, although apparently it tastes better in preserves. The plant grows as a large shrub or small tree, and takes a year for the fruit to mature, so they bear flowers and fruit at the same time. Arbutus is the foodplant for one of the most distinctive of Mediterranean butterflies, the Two-Tailed Pasha, Charaxes jasius.

Charaxes jasius
Arbutus unedo
In more shady areas we found many plants of Daphne gnidium in flower, which proved very attractive to butterflies. Daphne species are widely grown in gardens, but care should be taken with it as all parts of the plant are highly poisonous.

Daphne gnidium
Growing in shade we found a few plants of one of the most famous of all poisonous European plants, Deadly Nightshade Atropa bella-donna. The English name is easy enough to explain – the plant is the original source of atropine among other drugs, and was at one time used on poison arrows (also, allegedly, for murder by the wives of at least two Roman Emperors). The specific name refers to the use of eye drops derived from the berries as a cosmetic. The effect of these was to dilate the pupils, thereby (a) enabling the woman whom used them to give the impression she was interested in the man on the other side of the table, while (b) making sure she could not see him too clearly and thus be put off herself. Incidentally, do not try this at home.

Atropa bella-donna
Above the maquis level the climate is perfect for growing Sweet Chestnut, Castanea sativa. This was extremely important in the past, as it was the main source of carbohydrate in the local diet in the absence of ground suitable for wheat or barley. Flour made from chestnuts was used for bread or even beer (which is actually quite good), and the nuts were also eaten whole as in other parts of the world.

Castanea sativa
Above the fairly narrow chestnut growing zone pine forest dominates. Corsican Pine Pinus nigra corsicana is a local subspecies of Black Pine, and is adapted to grow best on the acidic soils of northern Corsica, which is mostly composed of granite.

Pinus nigra
Finally, the centre of the island reaches above the tree line, and you emerge into alpine vegetation. A prominent shrub to be found there is Alpine Juniper, Juniperus communis alpina, a prostrate version of a widely grown shrub or small tree. Juniper berries, when dried, are used in cooking and also provide flavour to gin.

Juniperus communis alpina
This concludes my survey of Corsica’s plants. Next time, I will cover the various insects and especially butterflies that we found on the island

(Photos are mostly mine, with some from Wikipedia)

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