無患子 Chinese Soap Berry or Soap-Nut Tree (Wuhuanzi)
無患子的果實富含皂素，只要置入水中，加以搓揉便會產生具有清潔功能的泡沫，能利用於各種清潔去汙之處；包括用來洗滌鍋具、衣服、頭髮、沐浴，甚至是珍珠黃金一類的珠寶等。因不含人造致癌物，會自然分解不汙染環境，可視為自然的清潔劑。
無患子為落葉喬木，樹型優美，秋冬之際，樹葉會全部落盡。在落葉前，葉子顏色會轉為鮮黃，極為美觀，因此常被種植為庭園景觀樹及行道樹。
The Chinese Soap Berry (Wuhuanzi) is originally from the low-elevation broadleaf forests of Taiwan, but has now spread over southern China, India, and southern Japan.
The fruit is rich in saponin, and when placed underwater and rubbed will produce cleansing foam, which can be used to clean pots and pans, clothes, the hair and body, and even jewelry such pearls and gold. Since it contains no man-made carcinogens, and it decomposes naturally without polluting the environment, it can be regarded as a natural detergent.
The Chinese Soap Berry is a deciduous tree with a beautiful appearance. Its leaves drop completely in autumn/winter, all turning bright yellow before withering. The aesthetics provided has made the Chinese Soap Berry popular as a garden tree and shade tree.