The Mexican feather grass has been imported by landscapers into Hawaii because of its drought-resistant qualities.

But the species is banned in Australia because of its potential to damage pastures and harm grazing animals.

"This plant is currently very uncommon in cultivation in Hawaii, but is being sold," said Rachelle Neville, manager of the Oahu Invasive Species Committee, a partnership of private, governmental and nonprofit organizations.

The presence of the feather grass here underscores what critics say is a weakness in plant importation laws that leaves Hawaii on the losing side of the battle with destructive alien species.

At stake are more than 10,000 species of plants and animals found nowhere else. The state is home to 25 percent of the endangered and threatened species in the United States — many on the brink of extinction.

The current system allows alien plants to enter the state unless they are on a federal list of noxious weeds or on a state list of restricted plants. But each list has fewer than 200 plants.

Critics say neither is adequate because there are about 300,000 species of plants in the world.

Moreover, scientists said putting a plant on the federal noxious weed list or Hawaii list of restricted plants takes too long — about two to five years — and allows it time to establish itself in the islands.

"That means you can bring in a great majority of the world’s plants," said Daniel Simberloff, a biologist and director of the Institute for Biological Invasions at the University of Tennessee. "Every year there are new invasive plants coming in. It’s not increasing exponentially, but it’s increasing."

Curt Daehler, a botany professor at the University of Hawaii, said that although there have been thousands of plants introduced to Hawaii, the impacts of most plants that have arrived in the last 20 years have not yet been felt.

"We see some of these plants escaping and spreading already," he said. "It may be a few more decades before we are spending money to control dense infestations in natural areas."

Simberloff and a number of other scientists support new rules that are being drafted by the U.S. Department of Agriculture that would require a risk assessment of all new plants imported into the United States to ensure they are not invasive.

The system would give scientists time to evaluate the plant before its entry.

A risk assessment process has also been proposed for new plants imported domestically.

"We just want to do background checks," said Christy Martin, spokeswoman for the Coordinating Group On Alien Pest Species. "That’s a common thing in our everyday life."

Lloyd Fischel, an orchid grower and president of Maui Farmers Union, said federal and state officials have failed to be proactive in expanding the list of banned plants and properly staffing inspectors.

Fischel said that while the state built a new plant and animal quarantine facility on Maui, it has also reduced staffing, including the elimination of the only on-site scientist.

"It’s unbelievable that they let that person go," Fischel said. "The government isn’t acting responsibly."

State agriculture board Chairwoman Sandra Kunimoto said the cutback in positions last year was a result of the state’s "dire fiscal situation."

"One of those positions on the … list was an entomologist position on Maui," she said. "Hopefully, as the economy improves, the entomologist position can be refilled."

She said staff from Honolulu and the Big Island are doing their best to cover Maui County.

Critics point out that the cost of neglect can be heavy.

Miconia calvescens, a plant that destroyed 70 percent of the Tahitian rain forest, was first imported into Hawaii by botanical gardens in the early 1960s.

But the plant was not placed on the noxious weed list until 1992, slowing efforts to eradicate it.

Scientists said that if a risk assessment screening had been conducted on miconia before it was imported, it would have saved the state millions of dollars.

Daehler said a professional landscaper was found planting Tibouchina urvilleana — a plant on the Hawaii noxious weed list — in 2006 at the Mililani Mauka housing development.

Invasive species committee staff and state agricultural officials worked with the landscaper to remove some 100 bushes.

"That plant never should have been in cultivation," Daehler said.

Daehler said many in the horticulture industry make conscientious efforts to avoid invasive plants.

"But all it takes is a few or even one of them promoting a serious invader — that can lead to high costs down the road."

The state Department of Land and Natural Resources said various government agencies spend $4 million annually in fighting invasive species here, including plants.