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Scientists at the Botanical Research Institute of Texas (BRIT) and University of Florida have solved a botanical mystery: Hawaii's wild blueberries originally came from temperate East Asia, not North America as expected.

The finding, in the American Journal of Botany, reveals an unusual 4,000-mile journey across the Pacific Ocean that happened about 5鈥�7 million years ago.

Hawaiian blueberries, called 驶艒helo by native Hawaiians, grow on six of Hawaii's eight main islands. The berries feed native birds and hold deep cultural meaning for Hawaiian communities. The plants show amazing variety in their leaves, flowers, and fruits. Although they are part of the large blueberry group (ca. 1400 species worldwide), the fruits of most 驶艒helo plants are actually red.

Using DNA analysis, the research team compared Hawaiian blueberries with their relatives around the world. The results showed that Hawaii's blueberries are most closely related to Vaccinium yatabei, a species found only in Japan.

"This is a rare pattern among Hawaii's native plants," said Dr. Peter W. Fritsch, co-senior author of the study and research scientist at BRIT. "Only 4% of Hawaiian plants are estimated to have come from temperate East Asia, whereas most arrived from North America or tropical regions."

The blueberries likely reached Hawaii by hitching a ride with migratory birds that still travel between regions around the North Pacific Ocean and the islands today. Birds most likely ate the berries in the north and carried the seeds across the ocean in their digestive systems.

Hawaiian blueberries are tough survivors. The plants appear to have come to Kauai "pre-adapted" to the wet cold conditions of Hawaii's high elevations, where they typically grow鈥攖heir ancestors evolved to survive cold temperate climates. They now often grow on fresh lava flows of the most recent island, Hawaii, where almost no other plants can live.

The story doesn't end in Hawaii. The research found that Hawaiian blueberries later spread to Southeastern Polynesia, where they mixed with a species from a different part of the blueberry group to create a hybrid species. The DNA evidence even suggests at least one has traveled back to coastal North America鈥攁n almost unheard-of reverse journey from islands to continents.

The timing matters. The blueberries arrived around the same time Kaua驶i, Hawaii's oldest major island, rose from the sea. Getting there early gave them millions of years to spread and adapt before competitors arrived.

Field and museum specimen observations, combined with a forthcoming DNA analysis based on populations from all the major islands, suggest 15 to 18 distinct species waiting to be formally recognized, a number much higher than the three currently recognized. This has important implications for the protection and conservation of 驶艒helo.