The evergreen buckthorn or Mediterranean buckthorn (Rhamnus alaternus L.) is an evergreen and dioecious small tree often in shrub shape. It can reach 6 m height, though usually it remains below 4 m. It belongs to Rhamnaceae family.
The leaves remain for about two years. These leaves are in alternating arrangement. They have a short petiole and a leathery, shiny, hairless, elliptic-lanceolate or lanceolate, 1-6 cm long lamina with a few small teeth on the margin (not always). The front of the leaves is deep green, while the back is paler. The veins are quite prominent on the front and opaque. The edge has a narrow, translucent border that can be seen opposite to light.
The flowers cluster in the leaf’s axils. They are small (about 3 mm in diameter), fragrant and greenish-yellow colour. The flowers have a calyx that divides into 5 lanceolate lobes and lack from corolla. Male flowers have reflexed lobes and 5 stamens, while female flowers have one pistil and their calyx’s lobes stand up. The fruits are 4 to 5 mm in diameter, slightly ovoid drupes with 2 or 3 grooves on the surface. The fruits contain 2-5 bones (usually 3) with seeds. At the ripe time, fruits turn from red to black. These fruits are toxic to humans. The seeds have a hidden into a groove, lipid-rich structure that encourages their dispersion by ants. The evergreen buckthorn is in blossom from February to May. The flowers are pollinated by insects. The fruits ripen mainly in summer. The evergreen buckthorn is a very variable plant depending on climatic and soil conditions. The Balearic variety is a less than 1-metre-tall bush that thrives in cracks of limestone rocks; it has twisted, usually lying on the ground branches, smaller leaves and fruits, and inflorescences with a few flowers.
The evergreen buckthorn puts up with the coldest winters that the districts of Bages and Moianès may have, as well as with the shade or the drought, and it thrives it doesn’t matter the chemical nature of the soil in terms of calcium carbonate.
The bark is laxative, and the leaves are astringent. The branches and leaves contain tannins; that’s why they were used to tan leather. The wood is hard, dense and homogeneous, and gives off an unpleasant smell. It is useful for turning and cabinetmaking. Evergreen buckthorn’s wood often replaces boxwood to make small things such as combs. At present, the evergreen buckthorn is used in reforestation and in gardening. It suits for fences because its perennial foliage and because it withstands pruning.
The evergreen buckthorn is native from the southern area of Europe with Mediterranean climate, northern Africa and the extreme southwest of Asia, where it lives mainly in scrublands, pine forests and sparse oak and holm oak forests. It also grows naturalized in the island of Gran Canaria, Crimea, California and New Zealand. In Australia, where it was introduced as a garden shrub, it has turned to invasive plant mostly in the coastal area of the southeast. In the districts of Bages and Moianès, the evergreen buckthorn is a rather frequent plant, even more in the Plain of Bages and its surroundings.
The evergreen buckthorn is similar to Phillyrea latifolia L.. It is quite common to find both species growing one next to the other. Phillyrea latifolia separates from the evergreen buckthorn by its opposite leaves that does not have prominent veins on the front side, neither translucent border on the margin.
The 1st picture shows a male individual in blossom, with flowers containing 5 fertile stamens. The 2nd and 3rd pictures display female individuals plenty of fruits.
[photos Florenci Vallès (1st and 2nd) and Jordi Badia (3rd)]
- See the article Convergència, in Catalan, by Jordi Badia.
- Flora of Bages – Herbarium of P. Font Quer.