A group of Boyds residents has filed suit against the county Planning Board over plans to build a cluster of homes on 434 rural acres in neighboring Clarksburg ­ just one example, residents say, of unwanted development encroaching on the Agricultural Reserve.

At issue is the on-again, off-again, on-again status of development plans for the Thompson Farm, located on Slidell Road. The plans have been in the works since 2002.

Residents claim that the Planning Board violated its own Rules of Procedure when it approved Jamison 427 Land Company's preliminary plan for the Thompson Farm last November after denying the same plan in 2003.

Residents contend that the board had no legal basis for granting Jamison's request for reconsideration since none of three criteria outlined in the board's Rules of Procedure for appeal were relevant. The reversal in the board's original denial hinged on the changed vote of Commissioner John Robinson, who residents said referred to himself as a "flip-flopper."

In a May 2 memo to the Planning Board from members of the Peach Tree Ridge and Boyds civic associations, group members wrote, " ... Maryland courts have long held, a mere change of mind is no basis for reversing a legally sound decision to reject a Preliminary Plan."

Residents also claimed that the plan should not have been approved because it does not "substantially conform" to either the Clarksburg Master Plan or the Agricultural and Rural Open Space Master Plan.

Thompson Farm sits within the county's Agricultural Reserve and is zoned for residential lots no smaller than 25 acres.

Jamison's preliminary plan calls for 17 houses on lots ranging in size from about 4 to 77 acres.

Here's the timeline of what has occurred so far.

On June 27, 2002, the Planning Board approved Jamison's preliminary plan with conditions. However, residents appealed that decision saying that Jamison had misidentified the subject land parcel in its presentation.

The board upheld that appeal and conducted a new hearing on the plan Dec. 11, 2003, at which time they voted to deny the application.

Jamison appealed that decision on June 24, 2004, and the Planning Board granted a new hearing held almost five months later. During that hearing on Nov. 4, 2004, the board upheld its original approval.

On May 2 residents filed another request for appeal with the Planning Board, and on May 20 they filed a lawsuit in Montgomery County Circuit Court requesting judicial review of the board's actions.

Marion Joyce, spokeswoman for the Planning Board, referred questions to Michele Rosenfeld, associate general counsel for Maryland-National Capital Park and Planning Commission.

Rosenfeld could not be reached for comment.

"The planning commission made an error in accepting the applicant's request for reconsideration," said Dolores Milmoe, of For a Rural Montgomery, who is one of four plaintiffs in the lawsuit. "They should have stood by the recommendation they made" when they denied the plan.

Some advocates of protecting the reserve worry that developing the land could lead to conflict between residents and farmers, she said. "They're setting up this culture clash where farming becomes a nuisance for suburban developments."

Milmoe said she worries what having a cluster of homes on small lots will do to the reserve's future in farming.

"The prime use of the Ag Reserve is agriculture. It's not supposed to be a residential zone," she said. "You're fragmenting the land, and you're taking it out of agriculture forever. That does not serve the long-term health of the Ag Reserve."

No court date has been set on the lawsuit, said David Fischer, the residents' attorney. Park and Planning officials have asked for more time to submit records in the case. Further action will likely not be taken until November, he said.