Local resident Bill Glover said he discovered the non-native aquatic plant hydrilla during a pond survey in August and contacted state officials, who verified the weed’s identity in mid-September.

Hydrilla is a fast-growing aquatic plant believed to have been introduced in the United States in the 1950s as an aquarium plant, first discovered in Florida and mainly found in southern states, according to information from the Massachusetts Department of Conservation and Recreation Web site. Until its discovery in Pembroke, hydrilla had been documented in just one other Massachusetts pond, in Barnstable.

Glover, who was trained by the local Weed Watchers program, said he decided to investigate the unknown plant after noticing its presence throughout Hobomock Pond.

“It’s such an invasive weed. It’s everywhere,” Glover said. Though the plant appeared to be a member of the Elodea family, another species of invasive weed, Glover said, “It just didn’t sit right.”

As a middle school science teacher, Glover said he knew the importance of research, so he grabbed a sample, got out his microscope and magnifying glass and searched for the plant on the Internet.

“One of the things that science teachers do is follow through, step by step, let’s go through the process of elimination. It didn’t fit the characteristics of any other type of weed, so I looked at what characteristics it did have, then backtracked,” Glover said. “I was able to identify within a couple of days that it was probably hydrilla.”

In September, Glover sent a sample to state officials and contacted the local Weed Watchers chapter about his discovery.

Hydrilla can grow an inch a day and reproduces rapidly, displacing native species and slowing water flow in a lake or pond, according to the DCR Web site.

“This is really basically a pond killer. It can reproduce in three different ways. It’s also very resistant to cold, and within a year’s time it can grow very rapidly,” Glover said.

Pembroke Conservation Agent Bob Clarke said the Conservation Commission is waiting to hear from DCR officials on a plan of action, including a source of funding to attack the weed. In the mean time, signs have been posted around the pond notifying residents of the hydrilla infestation and asking people to clean all fishing and recreational gear before leaving the water. People also are asked not to transport any plant fragments from the site.

“We’re ready to step in when we’re needed as soon as we’re needed,” Clarke said Monday. “We’re very concerned about it because of what it could lead to if it explodes more, if we can’t contain it where it is. From what we understand and have seen from photos in the southeast and other places, it has taken lakes over completely in not too big a time.”

Clarke said the commission was notified of the hydrilla discovery last week.

Michelle Robinson, an aquatic biologist with the Lakes and Ponds Program, a division of the DCR, said she is working to develop a short-and long-term plan for dealing with the plant and that no matter what the plan entails, the weed probably won’t disappear completely.

“It’s so well established that completely eradicating it from the pond is not impossible but very unlikely. We’re hopeful that with a short- and long-term management plan we can work to get it knocked way  back and then follow through every year with removing what does come back,” Robinson said. “It’ll take dedication.”

Robinson said she is impressed that Glover used his Weed Watchers training and took the time to identify the plant.

“Hydrilla is very easily misidentified,” she said. “He was very, very thorough.”

Although the plant could have been brought into Hobomock Pond by people, on fishing or boating gear or vehicles, Robinson said another likely cause is someone dumping the plant from an aquarium.

The Watershed Association is holding a meeting next Thursday, Nov. 20 at 7:30 p.m. at Pembroke Public Library to discuss hydrilla and other invasive weeds. Robinson said she plans to meet separately with both the Watershed Association and the Conservation Commission to discuss methods of managing the weed, as well as funding.