A team of plant specialists working for the Army on a contract with the University of Hawai'i yesterday continued a decade-long effort to reintroduce a plant that had become extinct in its native habitat of Kahanahaiki in Makua Valley.

Twenty-nine plants grown from seeds of the last known Cyanea superba — a palm-like plant that evolved and grew only on O'ahu in the Wai'anae Mountains — were placed in a container and flown by helicopter into Makua Valley, where a dozen workers planted them in the forest.

Once referred to as "the most glorious plant" by noted early-20th-century botanist and explorer Joseph Rock, the last wild C. superba died in 2003 — done in by predatory creatures and invasive alien plants.

"In general, there had been nothing to protect the plants from wild pigs and other predators for hundreds of years," said Matt Keir, botanist and rare plant program manager, who is overseeing the project.

"(Pigs) had stomped around and eaten most of the things," Keir said. "And then rats would eat all the fruits, and if they ever germinated, the slugs would eat the seedlings."

In the 1970s, there were just over five dozen C. superba plants remaining. By the late '90s, that number had dwindled to fewer than 10. By 2000, it was down to one.

Although the last wild C. superba died, it did not do so before it flowered. The resulting seeds were grown into saplings in a greenhouse above Makua Valley, near the plant's original habitat.

It takes about three years for one seedling to grow to around three feet tall, a height at which the plant can be re-introduced into the wild. Some 200 such plants have already been replanted in Makua Valley. Of those, about three-quarters have lived, Keir said.

But he said the eureka moment came recently when seeds from a few of those plants germinated on their own. A researcher noticed seedlings beneath a handful of reintroduced plants. Skeptical at first, Keir and other specialists investigated and were surprised and overjoyed to see it was a fact. In 10 years of working on the project, Keir said, that had never happened.

"We found seedlings for the first time, really ever," Keir said. "That's huge. That's exactly what we're trying to do. We're trying to out-plant little seed-making machines, basically. We grow them up so they'll survive well, put them out there, and we hope that they just dump seeds on the ground for the next 25 years.

"And if we can protect the forest around them, then hopefully we can just step back and let it happen."

That means putting up miles of fencing to keep out feral pigs and goats, eradicating rats and invasive species, and making sure slugs can't get at the seedlings.

The fencing has been highly effective, as have rat removal efforts. The program has a permit to test organic slug bait.

But human plant protectors must be vigilant, say team specialists.

"Slugs alone could wipe out the plant," said Keir, who said it not known exactly how C. superba were pollinated.

Some researchers believe it may have been done by honeycreepers. But the birds are no longer part of the area's habitat. Bees might do it. Otherwise, it will be up to humans, he said.

Kim Welch, environmental outreach specialist for the Army's natural resources program, said her team has high expectations that one day the "glorious" C. superba will again be part of the environment from which it evolved.

"We're very excited about this," she said.