Scientific Name : Pongamia pinnata (L.) Merr.
Common Name : Wild Bean
Chinese Name : 水黃皮, 水流豆, 野豆
Family : FABACEAE
Local distribution status : Native species
| Origins | Guangdong, Guangxi, Hainan and Fujian provinces in China. It also has distribution throughout Southeast Asia and Oceania. |
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| Ecology | The natural habitats of Wild Bean include areas near coasts, streams, ponds, as well as areas where the tides can be reached. In Hong Kong, the Wild Bean is a common native plant that can be found amongst coastal areas. |
| Applications | The Wild Bean has deep roots and a strong resistance to wind, drought and salinity, while not having particularly high requirements for soil. Therefore, it is a species designated for embankment protection and windbreaks in coastal areas. The flowers of the Wild Bean are bright, stunning and colourful. Having a beautiful tree forms which the tree crown is umbrella-shaped, with glossy emerald green leaves, making the species quite ornamental. Therefore, the Wild Bean is also currently selected as a street tree and greening species. |
| Meanings of name | The leaves of the Wild Bean are similar to those of the fruit tree Wampi (Clausena lansium (Lour.) Skeels, 黃皮 in Chinese). Additionally, it grows at the edge of water, giving it the Chinese name “Water Wampi (水黃皮)”. Applied in Traditional Chinese Medicine (TCM), its seeds exhibit functions of dispelling pathogenic wind, removing dampness, detoxifying the body, and destroying parasites. It is known as "Bean Floating-in-water (水流豆)" in TCM, since they are spread by floating pods which are carried by water currents. Since its leaves are pinnately compound (feather-like arrangement), the species epithet in its scientific name is "pinnata (pinnate compound)”. |
| Growing habit | Evergreen tree. |
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| Height | To 15 m. |
| Stems | Bark of trunk grey. Old branches with densely greyish white lenticels. |
| Leaves | Odd-pinnate. Leaflets 5 to 7, opposite, nearly leathery. Leaflets ovate, broadly elliptic to oblong-elliptic, apex shortly acuminate to rounded, dark green and glossy. |
| Flowers | Inflorescences axillary. Papilionaceous corolla white to pink. Petals clawed (narrowed base of petal). Standard (the upper or the outer petal) orbicular, involute. Keels falcate, slightly curved. Rachis, pedicels and calyx rusty pubescent. |
| Fruits | Legume elliptic to oblong, flattened, indehiscent. The short beak at the apex slightly curved. With 1 seed. |
| Seeds | Reniform, brown. |
| Flowering period | May to June in Hong Kong. |
| Fruiting period | August to October in Hong Kong. |
Scientific name above is based on Hong Kong Herbarium website : https://www.herbarium.gov.hk/en/hk-plant-database/plant-detail/index.html?pType=species&oID=6495
Scientific names from other databases
― Flora of China : Pongamia pinnata (Linnaeus) Merrill
― Plants of the World Online : Pongamia pinnata (L.) Pierre