Americans sent messages of love and appreciation Thursday to troops serving in the Persian Gulf as Valentine's Day 1991 fell in the shadow of a war half way around the world.

Yellow ribbons - a reminder of the troops overseas - adorned Cupid's arrow this year. While mushy messages, roses, chocolates and other heart-warming tokens were exchanged at home, the holiday was marred for thousands of Americans separated from their loved ones for months.But people worked to make the holiday less painful.

MCI Telecommunications Corp. posted a notice on a bulletin board in Saudi Arabia saying it was setting up free telephone calls back to the United States Thursday.

In scene after scene across the country reminiscent of the World War II homefront, neighborhoods and organizations rallied to keep up the troops' morale - as well as their own.

For weeks before Valentine's Day, groups collected signatures and messages on homemade paper valentines to be shipped to the gulf.

Others did it with yellow ribbons, like the gigantic streamer 900 feet long and a yard wide that was signed by hundreds of school children and adults in Tarrytown, N.Y.

In Houston, a 30-foot-tall, 48-foot-long valentine card proclaiming "You're in Our Hearts" was carted around town so Texans could send their best wishes. In another part of town the Adam's Mark Hotel staged a USO-type salute that organizers hoped could be piped live to the troops.

In San Diego, Miss America, Marjorie Vincent, planned to visit the Naval Hospital and the crew of the aircraft carrier USS Independence.

Apple Computer in Irvine, Calif., offered free use of the company's computers so families could send "letters from the heart" to a facility in Saudi Arabia where they would be sealed and delivered.

In Lake Worth, Fla., two brothers who own a nursery were giving away 3,000 plants to spouses of military personnel serving in the Persian Gulf.

David and Jeff Lee, who call their project "Operation Sweetheart," said they were distributing the plants from the back of a truck parked outside the MacDill Air Force Base near Tampa.

The brothers plan to travel to Homestead Air Force Base with another 1,000 plants this weekend.

For each flower, the pair was also sending individual letters overseas saying: "During Valentine's Day your sweetheart received a gift from you. This gift not only symbolizes the love you have for them, but also the love and admiration that the American people have for you."

And thoughout the country, many homes had a special light in the window burning through the night.

For those who don't, Nikka Brani of Utica, Mich., was organizing "Light Up Your Heart" - asking folks to turn on their porch lights at 7 p.m. Valentine's Day to show they are behind the troops.

"That's what the people who lived on my street did for my brother when he returned from Vietnam," she said.

"It was so beautiful that we all felt like crying."