Ailanthus-leaved bitterwood (Picrasma ailanthoides)
Picrasma ailanthoides (Nigaki): Description, Uses & Facts
Spanning the temperate and subtropical forests of East Asia, Picrasma ailanthoides grows as a deciduous tree celebrated for its medicinal properties and bitter wood. This resilient species plays a significant role in traditional Asian pharmacopoeias and forest ecology.
It is commonly found along forest margins, valley slopes, and riverbanks. The tree is particularly noted for its high concentrations of bitter quassinoids, which protect it from pests.
Taxonomy
- ∟ царство Plantae
- ∟ division Tracheophytes
- ∟ subdivision Spermatophytes (Seed plants)
- ∟ Angiosperms
- ∟ mesangiosperms
- ∟ eudicots
- ∟ Superrosids
- ∟ rosids
- ∟ malvids
- ∟ order Sapindales
- ∟ family Simaroubaceae (Quassia family)
- ∟ genus Picrasma (Bitterwood Tree)
- ∟ species Picrasma ailanthoides (Ailanthus-leaved bitterwood)
Morphology
The physical characteristics of this tree allow it to thrive in diverse East Asian climates. Its distinct foliage and bark serve as key identifiers in the wild.
- Bark: The bark is dark brown or reddish-brown, marked with horizontal lenticels and containing an intensely bitter principle.
- Leaves: The leaves are alternate and odd-pinnately compound, carrying multiple pairs of serrated leaflets that turn bright yellow in autumn.
- Flowers: Small, polygamous, greenish-yellow flowers form in loose, branched axillary clusters during late spring.
- Fruit: The fruit is a cluster of globose drupes, transitioning from green to red and finally to blackish-blue when ripe.
Flowering season
Late spring to early summer, typically from May to June
Applications
The dried stems and bark have long been utilized in traditional medicine across China, Japan, and Korea to treat fever, gastrointestinal infections, and skin disorders. Its bitter compounds are also extracted to formulate natural, eco-friendly insecticides and pest repellents.
In landscaping, the tree is occasionally grown for its attractive autumn foliage and ornamental fruits. Its hard, close-grained wood is also used for carving and making small utensils.
Interesting facts
The Japanese name for this tree is nigaki, which translates literally to bitter wood. It is so bitter that even a tiny fragment held in the mouth produces a long-lasting, intense bitterness.
In autumn, the compound leaves turn a brilliant shade of yellow, making it a prominent feature of the deciduous forest canopy. The species is highly resistant to air pollution, which has spurred interest in its suitability for urban forestry.
Geography of distribution
- China
- Japan
- Korea
- Russia
- Taiwan
Sources
- Plants of the World Online (POWO)
- World Flora Online (WFO)
- Global Biodiversity Information Facility (GBIF)