With art exhibits, tape recordings, films, books, plays, poetry, breakfasts, lunches and dinners, Montgomery County today is observing the anniversary of Martin Luther King Jr.'s birthday.

"I Have a Dream," the theme of one of King's most famous speeches, is being heard in many schools throughout the country this week -- in readings, from records and as the theme of student compositions -- as the late civil rights leader and Nobel Peace Prize winner is honored in a variety of schoolwide programs and classroom activities.

The county's official celebration takes place this evening, starting at 7:30, in the Montgomery College Fine Arts Building Auditorium at the Rockville Campus. There Jessie Rattley, president of the League of Cities and a councilwoman from Newport News, Va., will speak on eliminating poverty, racism and violence in the 1980s.

Local participants are to include Rose Eiland, president of the Black Campus Organization at Kennedy High School, the Montgomery County Youth Chorus and the Key Junior High Creative Movement Club. The event is the sixth annual county observance since the County Council established the Martin Luther King Jr. Commerce Committee in 1975, seven years after King was assassinated by a sniper in Memphis.

King's birthday is not a national holidy. County employes do not have the day off, but schools are closed.

Dr. Frederick Green, specialist on infant mortality and child abuse, is the keynote speaker for the City of Rockville's celebration of King's birthday. He is to speak today at 1 p.m. in the Rockville Civic Center Auditorium.

Green, associate director of Children's Hospital National Medical Center, last year chaired D.C. Mayor Marion Barry's committee on infant mortality. He currently is working on a special project in the treatment of sexually abused children at Children's Hospital.

Green will talk about health care for minorities and low-income families.

"There are still two classes of care for children, particularly in the health system," he said in a recent interview. "Whether we're in Montgomery County or Westchester County or Washington, D.C., the problems of the poor and the minorities remain essentially the same -- that being poor access to human services.

"There is an unacceptable gap between infant mortality of blacks and whites, with two to three times more black babies dying in the first 28 days of life," he said.

Green said he will share with the audience some vignettes of meeting King in Harlem, when Green was practicing medicine there.

County employes will mark the event at 3 p.m. in the County Office Building when Bob Woodson of the American Enterprise Institute, an expert on youth and the criminal justice system, will give a talk.

Alpha Phi Alpha, the black fraternity, will have its annual Martin Luther King Jr. memorial breakfast at the Holiday Inn on Georgia Avenue in Silver Spring. James A. Joseph, undersecretary for the Department of Interior, will be the guest speaker.

An exibit of photographers and prints describing the contributions of black Americans to the settling of the western frontier in the 19th century, put together by the Smithsonian Institution, is on display through Feb. 8 at Rockville City Hall and in the Rockville Library.