Close-up of naupaka papa (Scaevola coriacea, dwarf naupaka) plant. Dainty white half-flowers, small round dark purple fruit, and rounded green succulent leaves.
Naupaka papa (Scaevola coriacea, dwarf naupaka) plant. Photo credit: Gregory Koob.

Naupaka Papa and Native Hawaiian Plant Month: A Celebration of Rare and Endemic Plants in Hawaiʻi

By: Nanea Valeros, Public Affairs Officer, U.S. Fish and Wildlife Service

Naupaka papa (Scaevola coriacea, dwarf naupaka) is a flat-lying, non-woody shrub from the Goodeniaceae, or fanflower family. It has succulent green leaves, dark purple fruit, and cream-colored flowers where the tips of the petals cluster together on one side, appearing as though the other half of the petal tips are missing. It typically occurs in hot, dry coastal sites on low, consolidated sand dunes. Naupaka papa is one of my favorite native plants, and it is also endemic to Hawaiʻi, meaning it is found nowhere else in the world.

Naupaka papa (Scaevola coriacea, dwarf naupaka) plant on red dirt.
Naupaka papa (Scaevola coriacea, dwarf naupaka) plant. Photo credit: Gregory Koob.

Hawaiʻi is located in the middle of the Pacific Ocean, isolated from larger land masses (2,500 miles away from California) that make up the rest of the world. As a result, Hawaiʻi’s plants have evolved in relative solitude, creating unique biodiverse ecosystems and a flora with a high rate of endemism. In fact, 90% of native plants in Hawaiʻi are found nowhere else in the world. As a result of this isolation, there are nine endemic Scaevola species (S. chamissoniana, S. coriacea, S. hobdyi (extinct), S. gaudichaudiana, S. gaudichaudii, S. glabra, S. kilaueae, S. mollis, and S. procera) in Hawaiʻi; naupaka papa being the only coastal species of the bunch. The other eight species are only found in mountain/forest habitat. There is also an indigenous species, S. taccada, more commonly known as naupaka kahakai (beach naupaka), that can be found throughout the main Hawaiian islands as well as on other tropical and subtropical coasts all over the world. Naupaka kahakai can be easily distinguished from naupaka papa. Both are coastal naupaka; however, naupaka kahakai has white fruit and can grow taller and more robust, while naupaka papa has dark purple fruit and creeps along the ground like a vine. Furthermore, naupaka kahakai is very common and abundant in numbers, while naupaka papa is very rare and limited in numbers.

Naupaka kahakai (Scaevola taccada, beach naupaka) plant on a sand dune near the ocean.
Naupaka kahakai (Scaevola taccada, beach naupaka) plant. Photo credit: Gregory Koob.

In 1986, the U.S. Fish and Wildlife Service listed naupaka papa as federally endangered. Historical data show that this species was probably never very common, but many factors, such as development and the introduction of invasive plants and animals, have further limited where this species thrives. Naupaka papa historically occurred on Niʻihau, Kauaʻi, Oʻahu, Molokaʻi, Lānaʻi, Maui, and Hawaiʻi. Today, it can only be found on Maui and islets offshore of Molokaʻi. On Maui, there are 76 plants at three locations. On Molokaʻi, there are seven plants located on two offshore islets. As a result of such low numbers and the consequent high risk of extinction, naupaka papa is also a part of the Plant Extinction Prevention Program (PEPP).

Close-up of naupaka kahakai (Scaevola taccada, beach naupaka) flower. Half-flower is light purple and white.
Naupaka kahakai (Scaevola taccada, beach naupaka) flower. Photo credit: Gregory Koob.

PEPP is part of the Pacific Cooperative Studies Unit of the University of Hawaiʻi at Mānoa and is supported by State and Federal funding and private donations. As of March 2021, there are over 250 plants on the PEPP species list. In order to be added to list, a species typically has 50 or fewer individuals remaining in the wild, or are likely to have that number in the very near future. Most PEPP species have populations that are declining precipitously or individuals that are mostly found in a single location and therefore vulnerable to a single catastrophic event such as a hurricane or flood.

PEPP works to prevent the extinction of these rare plant species by collecting propagules (fruit, seeds, and cuttings) for long term storage, research, and propagation; protecting wild plants from plant, animal, and environmental threats; outplanting in the wild to create new populations; monitoring populations for growth, health and reproduction; and surveying for wild plants, new species, and species believed to be extinct. For naupaka papa, where majority of individuals are restricted to a single population, it will stay on the list until reintroductions to other historical locations are successful or until all individuals are adequately represented in cultivation, such as in seed banks or in botanical gardens.

Close-up of ʻohe naupaka (Scaevola glabra) flower. Half-flower is bright yellow and tubular.
ʻOhe naupaka (Scaevola glabra) flower. Photo credit: Gregory Koob.

With more than 420 threatened and endangered plants, Hawaiʻi accounts for 44% of all listed plants in the United States. These plants are very important for conserving biodiverse ecosystems, as well as for conserving different aspects of Hawaiian culture. For example, naupaka papa may have played a role in maintaining sand dunes by catching sand, or played a role in providing food and habitat for native insects. Those roles are very important for the coastal ecosystem and the species that live there (sea turtles, yellow faced bees, etc.), but what about the cultural component and their relationship to people?

Unfortunately, a lot of the cultural significance of naupaka papa (and many other rare and endangered plant species) has been lost. It is unknown if this species was used for lāʻau lapaʻau (medicine) or lei making like its relative naupaka kahakai. Traditionally, the leaves of naupaka kahakai were used as a natural sunscreen and to heal cuts, rashes, and stings. The leaves and flowers were also used to make lei. One of the cultural components of naupaka papa that we do know about is its role in haʻi moʻolelo (storytelling).

Close-up of naupaka kuahiwi (Scaevola mollis) flower and fruit. Half-flowers are purple and white, fruit are dark purple.
Naupaka kuahiwi (Scaevola mollis) flower and fruit. Photo credit: Gregory Koob.

A young man named Nanau and a young woman named Kapaka were in love. Pele (goddess of fire) was jealous of their love and tried to kill them. Fleeing for their lives, Nanau and Kapaka were separated — Nanau ran to the mountains, while Kapaka ran to the ocean. To save them from Pele’s wrath, Laka (goddess of the forest) turned the two lovers into flowering plants called “Naupaka.” Today, you can find Naupaka both ma uka (in the uplands) and ma kai (at the sea). The plant produces what appears to be a half flower, symbolic of a broken heart.

Moʻolelo (stories) like this one were passed down generation to generation and can be very insightful, both culturally and biologically. For example, this moʻolelo reinforces Pele’s wrath we always hear about in Hawaiian mythology, but we also learn that the endemic coastal and mountain species came from one plant. From “Origins of dioecy in the Hawaiian flora” (Sakai et al. 1995) and “Phylogenetics of the genus Scaevola (Goodeniaceae): implication for dispersal patterns across the Pacific Basin and colonization of the Hawaiian Islands” (Howarth et al. 2003), we know that eight of the nine endemic Scaevola species (including naupaka papa) in Hawaiʻi originated from a single colonization event. Colonization is when a plant population successfully immigrates naturally to an area, and becomes integrated into a new community. The ninth endemic species, ʻohe naupaka (S. glabra), was a separate colonization; and the indigenous naupaka kahakai was also a separate colonization. The eight endemic species from the single colonization all have similarities in flower shape and fruit color, with the exception of S. hobdyi (extinct), for which the fruit have never been observed. Even though naupaka papa is a coastal species, its fruit closely resembles the other endemic kuahiwi (mountain) species from the same colonization, rather than the coastal naupaka kahakai which came from a separate colonization. From a biological standpoint, this data reinforces what is learned from the moʻolelo.

Close-up of naupaka kahakai (Scaevola taccada, beach naupaka) fruit. Immature fruit are smaller and green, while mature fruit are larger and white.
Naupaka kahakai (Scaevola taccada, beach naupaka) fruit. Photo credit: Gregory Koob.

E hoʻolauleʻa kākou! Let’s celebrate Native Hawaiian Plant Month by acknowledging our native plant species, especially our rare endemic plants like naupaka papa. Native plants fill unique ecological roles and create healthy ecosystems for people; but they also fill cultural roles, which are often overlooked. What plants are native to the area in which you live? What are some cultural uses of the plant, or what is its cultural significance? Learn its traditional name and uses and share that with your family and friends. This month is a celebration for all that native plants are, their beauty, and what they can provide, and an opportunity to highlight some rare endemic species that we and our partners are working hard to bring back from the brink of extinction.

The U.S. Fish and Wildlife Service works with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. For more information, connect with us through any of these social media channels at https://www.facebook.com/PacificIslandsFWS, www.flickr.com/photos/usfwspacific/, or www.twitter.com/USFWSPacific.

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