The Maryland Senate awoke from five weeks of lethargy today as senators from Prince George's County launched a filibuster --the first of the legislative session--aimed at preventing changes in Gov. Harry Hughes' plan for legislative reapportionment.

The staid atmosphere that had marked earlier Senate gatherings gave way to biting sarcasm and passionate appeals on an issue of nagging concern to most legislators: new boundaries that will define their districts for the next 10 years.

Although the senators recessed tonight, some speculated that the filibuster could go on until Feb. 26, the date by which the legislature must act if it wants to prevent the governor's plan from taking effect automatically.

The speeches began over an amendment proposed by Senate President James Clark (D-Howard), an unassuming country gentleman whose passions have been aroused recently by what he calls the unfair treatment of his county in the governor's redistricting plan. For the past two weeks, Clark has waged an intensive one-man lobbying campaign to ensure that the populous town of Columbia, in his home base of Howard County, be preserved in a single senatorial district.

He said today that the governor made "a terrible mistake" when, on the advice of the Prince George's delegation, he proposed splitting Columbia into two districts, one of which would be dominated politically by the Laurel area of Prince George's County.

Clark's fight, described at first by some senators as an attempt to "save face" with his angry constituents, has transformed into much more. It has become a symbolic effort to retain the once mighty political stature of a rural area that is increasingly feeling the pinch from its more powerful urban neighbors.

Sen. Edward T. Conroy (D-Prince George's) said his county's Senate delegation sees it as a simple matter of protecting the county's opportunity to elect a senator from the joined district. He and other Prince George's senators rejoiced when Hughes divided Columbia and they don't want to see their dream of another senator shattered now.

Although Clark and his allies said they have the votes to pass his amendment, it is unlikely they can stop the long-winded speeches.