Murasaki had prepared the floral offerings.
She chose eight of her prettiest little girls to deliver them,
dressing four as birds and four as butterflies.
The birds brought cherry blossoms in silver vases,
the butterflies yamabuki in gold.

From "The Tale of Genji" by Murasaki Shikibu, translated by Edward G. Seidensticker (Penguin Books)

The simple, pure-yellow flowers of the yamabuki are borne in arching sprays with tender, bright-green leaves, and can still be found growing wild in the mountains. In literature, its Japanese name is sometimes translated as "mountain rose" or "yellow rose," although the original implies a mountain breeze or spray. William Kerr, the first plant hunter to live in China, introduced the shrub to the West in the early 1800s, where the double variety was affectionately called "bachelor's buttons," because of its showy spring display.