
One of the more curious things to see along Hawaii’s trails are the odd “half-flowers” of mountain naupaka or “naupaka kuahiwi” in Hawaiian. While naupaka blossoms are not incomplete, they appear to be only half a flower because all the petals are on one side. So distinctive are these “half-flowers” that several Hawaiian legends exist that account for their unusual appearance.
Mountain naupaka evolved from beach naupaka. Beach naupaka is indigenous to Hawaii and throughout the tropical and subtropical zones of the Pacific and Indian Oceans — it has buoyant white seeds that can float on the ocean to reach distant shores. Mountain naupaka on the other hand, is endemic to Hawaii – all 6 species of are found no where else in the world and trace their origin to beach naupaka.

This is a photo of beach naupaka or naupaka kahakai (Scaevola sericea) at Mokuleia on Oahu. Since all of the petals are on one side of the flower, it blossoms are shaped like a fan and look like half a flower. Its “half-flowers” grow from the main stalk under its leaves. Note how the leaves of beach naupaka are round with smooth edges.

This photo shows the “half-flowers” of the most common mountain naupaka — Scaevola gaudichaudiana. Mountain naupaka differs from beach naupaka in that its flowers have a delicate sweet fragrance that beach naupaka lacks.

Naupaka kuahiwi is found at higher elevations in the mountains. Note how the leaves of mountain naupaka differ from beach naupaka. Mountain naupaka leaves are pointed and have serated edges. Also note how the flowers of mountain naupaka grow on stems whereas the flowers of beach naupaka grow directly on the main plant stalk beneath the leaves.

Naupaka kuahiwi is found at higher elevations in the mountains. In this photo taken along the Manana trail above Pearl City on Oahu mountain naupaka grows as shrubs 5-10 feet tall.

There are several Hawaiian legends that tell the origin of the beach and mountain forms of naupaka, both of which produce these unusual half-flowers. In one version, a princess was forbidden to marry her true love, a fisherman, because he was a commoner. As they parted ways forever, she tore a flower in half, giving one half to him and keeping the other half for herself. She then returned to the mountains where her family lived. Broken-hearted, they both cried and planted their halves of the flower. Each half grew and became the two forms of naupaka – the beach naupaka (naupaka kahakai) and the mountain naupaka (naupaka kuahiwi).
All photos except the first one appear to be typical of Scaevola gaudichaudiana found only on O’ahu and Kaua’i.
S.chamissoniana is similar and found on Maui Nui (Mo,L,M) & Hawaii Island.
My mistake… you are correct. Thanks for pointing out what it really is. I’ll make the correction.