Tavern on the Green has had a decidedly rotten year, what with its bankruptcy, loss of lease, and worker protests. Now, it can add the Department of Parks & Recreation to its list of woes: the department is claiming that it, not the LeRoy family, owns the name of the 75-year-old restaurant, which the LeRoys began operating in 1973. The restaurant’s owners claim that the Tavern on the Green trademark is worth $19 million, and include it among their business assets. Lawyers for the LeRoys say that the city doesn’t have much of a case, since this is the first time in 31 years it’s disputed ownership of the Tavern name, which the LeRoys trademarked in 1981. The city, which recently leased the restaurant to Dean Poll, says better late than never.