About Koelreuteria elegans (Seem.) A.C.Sm.
Koelreuteria elegans, commonly called flamegold rain tree, is a deciduous tree that grows 15 to 17 meters tall. This species currently includes two subspecies: K. elegans ssp. elegans, which is endemic to Fiji, and K. elegans ssp. formosana, which is endemic to Taiwan. The subspecies formosana, commonly known as Taiwanese golden rain tree, is widely planted as a street tree across tropical and subtropical regions worldwide. Koelreuteria elegans flowers in autumn. Its flowers are small, reaching up to 5 millimeters in diameter, and grow in terminal panicles. Each flower has four to five unequal petals, which are butter-yellow with a red base. Flowers contain eight stamens with hairy filaments, and the three-celled ovary is red during flowering. The fruit is a bladder-like, inflated capsule that is red to green when unripe, and turns brown when fully mature. The capsule eventually splits into three valves; each valve is suborbicular, and holds one or two black seeds, rarely three to four. Taiwanese golden rain tree is classified as a declared weed in many regions globally, especially in Brisbane, Australia and Hawaii.
