A number of paintings of wildflowers by Louis C. Linn are now on display in the lobby of the administration building of the National Arboretum. According to Dr. Frederick G. Meyer, director of the herbarium, they have the highest degree of structural accuracy and fidelity of color that is possible in the medium of watercolors.

"All of the paintings were done on location, and they convey the spirit and vitality of the living flowers," he says.

Meyer is rated as one of the top experts in this field. He is the taxonomist chosen by Wilhelmina F. Jashemski, University of Maryland archeologist in charge of Pompeii excavations, to provide on-site identification of plants that had been buried under seven meters of volcanic ash since 79 A.D.

Louis Linn wanted to alert people to the wildflowers so they would no carelessly step on some small half-hidden bloom or pass by with an unseeing eye.

He had no degree in botany but had always painted. He attended evening classes at the Corcoran Art Gallery in Washington while in high school; then studied two years full-time at the Academy of Fine Arts in Philadelphia. Still later he painted with the Art Student's League in New York.

When he came home from World War I, he decided to devote himself to painting.

He lived on the Potomac River near Washington, a wildflower haven with woods, rich open ground and river banks.

Botanists from the universities around Washington encouraged him to paint the wildflowers. He never went out without a sketch pad and watercolor box, and usually sketched and painted a flower from two positions. He never picked the flowers. Once he located a plant in bud, he would wait for it to reach full maturity.

He made numerous trips to Main, Long Island, western New York state, the pine barrens of New Jersey, the mountains of Maryland and Virginia and the southern Appalachians, the bogs of the Carolinas and northern Florida.

The paints accumulated over a period of 13 years.

Then Louis Linn died suddenly.

More than 25 years later, his wife, Ruth Hearn Linn, took his paints to Meyer. "They were as timely when they were done," he told her, "and while a number of field guides existed with beautiful color photographs, there was not yet in the United States a field book of painted flowers in which every detail was in focus."

Meyer sent her first to Dr. John Churchill, who had prepared a herbarium for the Univeristy of Michigan. He too was enthusiastic and patiently and painstakingly researched each plants and updated the taxonomy. For months he devoted a day of each weekend to the project.

Meyer then set himself the task of supervising a script. He made the library of the National Arboretum available to her and after 13 months, three writings and numerous trips to the herbarium, a text was finally evolved. He has read, corrected and reread it.

The book, "Eastern North America's Wildflowers, A Full-Color Guide, 373 Life-Size Paintingss," by Louis C. Linn, text prepared by Ruth Hearn Linn, 277 printed pages, $9.95 paperback, was published by Dutton.