Scaevola taccada (syn. Scaevola sericea) is found on tropical beaches of the Pacific and Indian Oceans. Due to its large native range, Scaevola taccada goes by many different local names. In Hawaiian, it is called naupaka kahakai. English common names include beach naupaka, beach scaevola, fan flower or half flower.
These large evergreen shrubs can reach 3-4 m in height, and the glossy, light green leaves can range from 5-15cm long. The plant is able to quickly colonize areas because it easily roots wherever branches come in contact with the ground. For this reason, it was introduced to coastal areas outside of its native distribution to be used for erosion control. However, in some places such as Florida, it has become an invasive weed.
The flowers are produced throughout the year and are composed of five white to pale purple petals in a distinctive fan shape. The flowers are hermaphroditic, meaning they have both staminate (pollen-producing) and carpellate (ovule-producing) structures. They also exhibit protandrous flowering — this means the anthers release pollen before the stigma of the same flower is receptive. For more information on protandry, see the Wikipedia entry.
The fleshy white fruit contains lightweight, buoyant seeds. The seeds remain viable even after prolonged exposure to sea water, but will only germinate in fresh water. Images of the fruit, as well as general growth habit, are available from Insect Images: Scaevola taccada.
It is interesting to note that there are several Scaevola species in Hawaii occupying a range of habitats. For example, Scaevola taccada is found on beaches, whereas Scaevola gaudichaudiana is found in the mountains. This is believed to be an example of adaptive radiation, a situation where rapid speciation occurs to fill many ecological niches.
Hawaiian legend offers another explanation for at least two of the species. A long time ago, two lovers upset the Volcano Goddess Pele. As a result, one was turned into beach scaevola. The other fled into the mountains and was turned into mountain scaevola — the distinctive “half flowers” found on each plant represent the eternal separation of the lovers. Was it evolution or the wrath of a goddess? For photos of the different Hawaiian Scaevola species, please see Scaevola from the Hawaii Native Plants site.