Politicians, wildflower aficionados and a whole lot of Texans turned up to celebrate "An Afternoon in the Country" at Averell and Pamela Harriman's home in Middleburg yesterday. The event benefited -- and celebrated -- The National Wildflower Research Center, a Texas-based nonprofit organization founded by Lady Bird Johnson in December 1982.

In a speech to the crowd of 300 supporters, each of whom paid $150 to attend, the former first lady explained her motivation in starting the organization: "Some people wonder," she said, "why, in a world that's beset with nuclear destruction . . . why do I think about wildflowers?

"Well, it's been in my heart forever . . . I have found this world a joy, this country, with all its diversity. I want the states to specialize in what is their own . . . I want to keep the beauty that's given me such joy."

Sen. John W. Warner (R-Va.), Sen. Robert J. Dole (R-Kan.) and Transportation Secretary Elizabeth Dole were cochairmen of the benefit along with the Harrimans.

Asked about his involvement, Warner explained: "I grow a lot of wildflowers . . . The only thing I can take credit for is the weather. This is my state and I'm the senior senator; I can take credit for the weather."

Guests meandered through a tent filled with crafts from a dozen boutiques, half by Virginia exhibitors and the rest by people from other areas. The sellers donated a percentage of their proceeds to the National Wildflower Research Center. But as H. Elaine Jackson, director of a Capitol Hill gallery, explained, "It was obviously an excellent opportunity in terms of the clientele."

After browsing through the crafts, the crowd dined on a buffet supper that included such countrified fare as "wildflower fritters," apricot-glazed lamb, corn bread and country pa te'.

Lady Bird Johnson's daughters, Luci Johnson and Lynda Robb, came to show their support, and Virginia Gov. Charles Robb said he was "not personally involved with the research center . I am here supporting my mother-in-law and because my wife said 'Honey, this is your altar call. Get going.' "

Although not everyone there was involved with Johnson's project, everyone applauded her efforts. "The most exciting thing about this whole thing is its universal acceptance across the nation," said Nash Castro, president of the National Wildflower Research Center.