Species list


Frangula alnus

Alder buckthorn

Alder buckthorn (Eng), arraclán (Spa), fràngula (Cat), zumalakar, oila-karana (Baq), sanguiño (Glg), sanguinheiro (Por).


DID YOU KNOW...? Its fruit is highly toxic and may cause stomach and intestinal problems.


The alder buckthorn is a very branching shrub or small tree that can be up to 12-15 m tall in optimum conditions. Its bark is smooth and reddish when young, but becomes grey with age. If you scratch the bark or break a branch it smells bad, which is why in Extremadura it is known as el hediondo, ‘the stinking one’. The leaves are 2-14 cm long, 1-6 cm wide, deciduous, simple, alternate, oval, shiny on the upper side and matt on the underside. They are somewhat reminiscent of beech leaves, but lack the tiny hairs that these have on the margin. The flowers are greenish and inconspicuous, and the fruits are pea-sized, black when ripe, and contain 2 or 3 seeds. Flora Iberica differentiates two subspecies on the Iberian Peninsula:

Frangula alnus Mill. subsp. alnus. The leaves are deciduous and comprise a blade 2.5-11 cm long and 1.5-6 cm wide. They are broadly oblong-lanceolate, obovate, oval or almost orbicular, with the tip being obtuse, acute or acuminate.

Frangula alnus Mill. subsp. baetica (Willk. & É. Rev.) Rivas Goday. The leaves are deciduous or stay om the tree for two years and comprise a blade 5.5-14 cm long by 2.5-6.5 cm wide. They are usually lanceolate to oblong-lanceolate, with a sharp, gradually attenuated tip.


This species occurs in a scattered pattern, seldom forming stands, and tends to accompany humid, shady forests. It is associated with watercourses or bodies of water, from sea level to 1200 m, on all soil types, as long as they are well developed and the ambient humidity is high. Its presence indicates nearby groundwater.


The alder buckthorn lives in Europe, Asia and northern Africa. It is found widely dispersed across the Iberian Peninsula, but it is most abundant in the north and west. The subspecies alnus is distributed all across the peninsula, although the subspecies baetica is much more localised and found in certain parts of the of Sierra Madrona range, Valle de Alcudia, and the Algeciras, Aljibe and Aracena mountains.