Bagrem

Black locust is a hardwood tree belonging to the tribe Robinieae of the legume family. Another common name is false acacia.

Origin and Growth

The species is native to a few small areas of the United States, but has been widely planted and naturalized elsewhere, including temperate North America, Eurasia, and Africa. As a nitrogen fixer with rapid juvenile growth, it is widely planted for ornament, for shelterbelts and for land reclamation. When growing in sandy areas the tree can enrich the soil through its nitrogen-fixing nodules, allowing other species to move in. It is typical of young woodlands and disturbed areas where sunlight is plentiful and the soil is dry. The tree is generally 12 to 18 m (40 to 60 ft) tall.

Flowers and Honey

The flowers open in May or June for 7-10 days, after the leaves have developed. The flowers hang in loose racemes typically 10-20 cm (4-8 in) long, and they are cream-white, rarely pink or purple. They are about 2.5 cm (1 in) wide and produce large amounts of nectar. Black locust is a major honey plant in the eastern US, and in many European countries it is the source of acacia honey. Blooming is short and the tree does not consistently produce a honey crop year after year.

Food Uses

In Liguria, Italy, and Romania the flowers are sometimes used to produce a sweet and perfumed jam. The flowers are eaten as beignets after being coated in batter and fried in oil, and they are also eaten in Japan, largely as tempura.

Chemistry

The odor of the flowers indicated the presence of methyl anthranilate, and the flowers were later shown to contain this ester. The extract was found to contain anthranilic acid methyl ester, indole, benzyl alcohol, linalool, α-terpineol, heliotropin and traces of pyridine-like bases. Aldehydes and ketones are also present in the extract, and probably nerol as well. The oil contained 9 per cent ester, computed as methyl anthranilate. Its alcoholic solution had a decided blueish fluorescence. The petals show high concentrations of the monoterpenes (Z)-ocimene and linalool, followed by geranyl nitrile and β-myrcene. The volatiles of Robinia honey are mainly terpenes in high concentrations, including linalool, cis-linalool oxide and hotrienol.

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