Koelreuteria paniculata goldenrain tree

Goldenrain tree leaf silhoutte. From Trees of Stanford and Environs by Ronald Bracewell

One of the five traditional memorial trees of ancient China, the goldenrain tree was designated for the tombs of high-ranking officials (see also Styphnolobium japonicum). The pinnate leaves, about a foot long, are of remarkable beauty, with the leaflets showing a pleasing variableness in lobing and serration. In early summer, large panicles (whence the species name) of small yellow flowers appear; these develop into inflated, papery, lantern-like fruit reminiscent of bougainvillea bracts. Within are three hard round seeds that have been used for rosaries. A yellow dye can be extracted from the flowers, while the leaves will dye white cloth black when boiled with it. Autumn foliage is a mix of yellow, brown, and russet.

Our largest specimen grows at the right of the entrance of Gates Computer Science Building. A formerly fine planting along the east side of Schwab Residential Center is now reduced to three trees near Jane Stanford Way; across the street from them are two K. bipinnata. One K. paniculata remains of two that were interplanted among K. bipinnata near the lawn and sand volleyball court at Willis Court in Rains Houses.

These sites offer an excellent opportunity for comparison. K. paniculata blooms several weeks earlier. Its lanterns are conical, tapering to a point. They begin greenish-tan, developing a touch of rose, and can linger on the crown until the next flowering season. K. bipinnata, by contrast, bears lanterns that are more rounded and colorful, often emerging with a rosy-purple blush; its leaves are fully bipinnate, a trait readily visible at a glance.

Name derivation: Koelreuteria – after German botanist Joseph G. Kölreuter (1733–1806); paniculata – see text above.