At Foster Botanical Garden is a tree that, when in flower, sends out sunny bursts of warm, orange-gold color.

This is the red saraca, introduced to Hawai'i by legendary botanist Joseph Rock in the early 1900s.

The tree's tiny flowers are about three-fourths of an inch across, but they can form huge clusters — this season, the largest cluster I have measured on the Foster Garden tree is 12 inches wide!

The center of the flower, or "eye spot," turns dark purple with age. The blooms emerge from the tree's main trunk and limbs as well as along the smaller branches.

With all its colors, it seems astonishing to learn that the red saraca flowers have no petals. None. Without the petals, the calyx (usually the green floral parts that cover and protect the flower when in bud) attracts pollinators. The garden's honey bees are drawn to the dazzling colors and slight fragrance of the flowers.

The tree develops long, flattened pods that taper at both ends, and contain four to eight oblong seeds. The seeds don't keep well, so if they are to be used for planting, it should be done as soon as possible.

Native to the Indonesian islands of Java and Sumatra, the moderately slow-growing red saraca is an understory, rainforest tree, where it has a tendency to grow leggy and can reach a height of 30 feet. When grown in a sunnier location with some shade, fertile soil, plenty of moisture (but good drainage), the tree tends to have a fuller form.

In India, the bark is reportedly used to treat infections, as well as mental disorders. Bark, flowers and seeds are also said to be helpful against some gynecological ailments.

A close relative of the red saraca (Saraca declinata) is the asoca, or sorrowless tree (Saraca asoca). It is believed that the Buddha was born under an asoca, which is native to India, Sri Lanka and Myanmar. The name asoca means "without grief," and the species is often planted near Buddhist temples. On O'ahu, you can see a specimen on the grounds of the Honpa Hongwanji temple on Pali Highway.

Winnie Singeo is director of the Honolulu botanical gardens. Reach her at hbg@honolulu.gov.