Prunus padus, known as bird cherry, hackberry, hagberry, or Mayday tree, is a flowering plant in the rose family. It is a species of cherry, a deciduous small tree or large shrub up to tall. It is the type species of the subgenus Padus, which have flowers in racemes. It is native to northern Europe and northern and northeast Asia, and is grown as an ornamental in North America. Distribution Prunus padus is native to eastern, central and northern Europe and spans central latitudes of Asia, including Japan. Its distribution includes the all of Western and Central Europe north of the Pyrenees and the Alps and south of the treeline with small pockets also found in Iberia and Northern Italy and even parts of North Africa. It also inhabits all of Eastern Europe north of the Balkan Mountains and the Steppe, as well as in the Caucasus. In Asia it is found throughout the forests of Siberia, the Russian Far East, Korea, Hokkaido, and parts of China with pockets in the Himalayas. The Mayday tree is abundant as an introduced species in Anchorage, Alaska, having been planted in great numbers by landscapers and homeowners. Description The fruit is astringent due to its tannin content. There are two varieties: European bird cherry Prunus padus var. padus, Europe and western Asia. Asian bird cherry Prunus padus var. commutata, eastern Asia. Ecology The flowers are hermaphroditic and pollinated by bees and flies. The fruit is readily eaten by birds, which do not taste astringency as unpleasant. In Eurasia, the Bird-cherry ermine moth (Yponomeuta evonymella) uses bird-cherry as its host plant, and the larvae can eat single trees leafless. In North America the tree is often attacked by the black knot fungus. Poison The glycosides prulaurasin and amygdalin, which can be poisonous to some mammals, are present in some parts of P. padus, including the leaves, stems and fruits. Uses The fruit of this tree is seldom used in western Europe, but, long ago, may possibly have been used as a staple food far to the east. According to Herodotus (writing some 2500 years ago) a strange race called the Argippaeans, all bald from birth, who lived in an area identifiable possibly as the foothills of the Urals, would pick the bean-sized fruits of a tree called "pontic" and squeeze from them a drinkable black juice, making afterwards, from the residue of the pressing,