Japanese bitterwood (Picrasma japonica)

Japanese quassiawood Japanese picrasma Korean quassiawood
Silhouette: T. Michael Keesey / License

Picrasma japonica (Japanese Quassiawood): Guide and Facts

Spreading across the temperate forests of East Asia, Picrasma japonica attracts interest due to its striking pinnate foliage and historical use in traditional herbal remedies. This deciduous tree adapts well to various soil types and is recognized for the intense bitterness found throughout its wood and bark.

It forms an integral part of deciduous woodland communities in mountain regions. The tree is also grown in botanical collections for its ornamental fall foliage.

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 japonica (Japanese bitterwood)

Living Pulse

Morphology

This deciduous tree grows to heights of 10 to 15 meters, exhibiting a rounded canopy. The leaves are alternate and pinnately compound, consisting of 9 to 15 leaflets with serrate margins.

In late spring, it produces small, inconspicuous, greenish-yellow flowers arranged in lax axillary cymes. These flowers transition into globose drupes that turn red and then black upon reaching maturity.

The bark is smooth, dark brown or greyish-yellow, and marked by prominent lenticels. Every part of the vegetative structure carries a strong, bitter flavor.

Flowering season

Late spring (May-June)

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Applications

The bark and wood of this tree have long been utilized in traditional East Asian medicine. They serve as a natural stomachic, febrifuge, and insect repellent due to the presence of quassinoids.

Extracts are also employed in agriculture as organic insecticides to protect crops from pests. Additionally, the wood is occasionally used for small wooden crafts and utensils.

Interesting facts

The bitter compounds in the bark are so concentrated that even a tiny fragment can leave a lasting bitter taste on the tongue. This substance is considered one of the bitterest natural compounds known.

During the autumn season, the compound leaves turn a vibrant, bright yellow. This colorful display provides high ornamental value in forest gardens.

Geography of distribution

  • Japan
  • South Korea
  • China
  • North Korea

Sources

  • Plants of the World Online (POWO): Picrasma japonica (A.Gray) Diels
  • World Flora Online (WFO) Database
  • Global Biodiversity Information Facility (GBIF)
  • Tropicos database, Missouri Botanical Garden

Technical Information

External Databases: GBIF, POWO, Tropicos