Buc-ee's, the local convenience store chain known for clean restrooms, cheap gasoline and its cartoon beaver mascot, is trying to stop a Nebraska company from muscling in on the Texas market with plans to build stores called Bucky's, the latest development in a decadelong dispute between the dueling convenience store chains with names that sound the same.

Eleven years ago, both filed for trademarks months apart to protect their growing companies. After a legal battle, the two reached a truce: Bucky's in Nebraska agreed that the Texas company could continue to use "Buc-ee's" because the names, logos and market areas of the two operators were different enough that consumers were not likely to be confused, according to the 2009 consent agreement.

The agreement allowed the two chains to coexist because of their geographic distance, said Steve Levine, a trademark lawyer in Dallas. The peace lasted eight years until Bucky's owner, Buck's of Omaha, broke the truce with its Texas expansions plans.

"Bucky's in Nebraska has really, really upped the ante by moving into Texas," Levine said.

Buck's has teamed up with developers to begin building at least six Bucky's convenience stores within the next year, including locations in Houston and Nassau Bay, according to the lawsuit Buc-ee's filed Tuesday in U.S. District Court in Houston. Buc-ee's alleges that Buck's - which does business as Bucky's in the Midwest -is trying to confuse the public by using a similar name and is seeking a court order to stop the plans from moving ahead.

Bucky's has already bought property, applied for zoning permits and obtained liquor licenses for an unspecified number of stores, the lawsuit says.

"We must take action to ensure that our brand integrity remains intact and that our customers' interaction with Buc-ee's is what they have come to know and expect," Beaver Aplin, Buc-ee's CEO and co-founder, said in a prepared statement.

Bucks did not return calls for comment.

Buc-ee's accuses its rival of trademark infringement and unfair competition. Shawn Bates, a commercial trial lawyer who handles trademark cases in Houston, said the case will likely revolve around the issue of consumer confusion. The question is where people who see a sign for Bucky's will get off the highway believing they're heading for a Buc-ees, with its wide selection of Texans' favorite foods and Lone Star tchotchkes.

"In my mind, when people say Buc-ee's, they're talking about the beaver," not how it's spelled, said Bates, a Buc-ee's fan who stops at every opportunity for the honey pepper-flavored jerky.

From its beginnings in Lake Jackson in 1982, Buc-ee's and its 32 stores have become a famous Texas rest stop. Signs up and down the state's highways draw in travelers for snacks, drinks, and even home accessories such as candles, dishes and art.

"There's always something new to see in there," Bates said. "It's not just another road stop."

Buck's used Bucky's for the first time in 1982 at one of its stores in Omaha, according to court documents. Since then, the stores, which adopted the nickname of its founder Steve Buchanan, have expanded the corporate footprint.

Bucky's has nearly 50 convenience store locations in the Chicago area, 32 in Omaha and three in St. Louis, according to the company's website. Customers who belong to the "Moo Club" - which features a cartoon image of a cow - are eligible for free milk.

The stores sell traditional traveler items such as sandwiches, fountain drinks and coffee along with a line of logo tee-shirts and sweatshirts. The larger stores have at least 20 gas pumps.

The dispute between Buck's and Buc-ees started in 2006, according to court documents. Buck's filed for a trademark registration with federal authorities in January that year, and Buc-ee's applied three months later in April.

Buck's sued Buc-ee's in 2008, claiming unfair competition and deceptive trade practices. The lawsuit - and trademark dispute -were resolved when Bucky's agreed Buc-ee's could continue to use its name.

The lawsuit against Bucky's is not the first time that Buc-ee's has gone after its competitors. Buc-ee's sued the San Antonio-based operator of Choke Canyon Travel Center in 2015 for promoting its gasoline, food and other travel essentials with its grinning, lip-licking, hat-wearing, finger-pointing alligator. The alligator sits in a circle - much like the Buc-ee's beaver - and decorates a wide range of products from snacks to T-shirts. That case is ongoing.