Seizing a machete and whacking from Panama to Costa Rica in 1928, Harold May cleared the way for the great highway that runs between two continents, though (as he would modestly say) others helped.

Later he became a civil engineer and was intimate with concrete and dams. But inside him was a gardener trying to be born. At first, no bigger than a lichen.

First, an orchid plant showed up in the living room. Then a lot more. Then the dining room overflowed with God's most ingenious handiworks. Then the kitchen:

"When they got into the bedroom, I said that's it, IT, and built a greenhouse. It all came from seeing these beautiful flowers in the tropics. Now I have nine greenhouses, and one built over a 90-foot-long swimming pool. I took the water out, and have acacias in one end and bananas in the other.

"The greenhouse is wider than the pool, so I have a lot of orchids along the side. We also have several thousand anthuriums and . . ."

"You grew those?" a reporter asked.

"Not these. My wife goes to pieces if I cut any of ours, so we buy them from Hawaii."

May, when last sighted, was darting about the great heated courtyard of the Pan American Union building like a hound in a lobby full of goats. Unable to settle.

"I brought 500 plants with me," he said, as the gorgeous cattleyas, laeliacattleyas and brassolaeliacattleyas waited patiently in their pots. He managed to bang an axle of his truck coming down from Glen Mills, Pa., ruining a wheel (for the capital has no monopoly on pot holes, merely the showiest) and arriving late. He was assisted in anxiety by Margaret Silva, wife of the Costa Rican ambassador, who got May to bring his orchids down for an American orchids display that opens this morning.

(10 a.m. to 5 p.m. today through March 2, free.)

You may suspect that all this interfered with May's career in civil engineering.

"I remember the day in 1967 very well. I got out of my office and never went back. Didn't even go back to get my engineering books. It's been orchids ever since. I've never been so busy or worked harder. Look at that cymbidium. Nice, isn't it? Careful of the paphiopedalums there." (A clumsy foot approached them closely.)

"If other people had something like these flowers to interest them, they'd all live to 100. This courtyard is certainly one of the most beautiful places to display orchids, isn't it? So many of the wild species are now rare, or threatened with extinction. I've shipped many orchids back to their native countries."

Margaret Silva said it was really a shame that so often when highways are cut through in the tropics, people really have no idea what may be lost.

May, the engineer of yesteryear was lost in a phalaenopsis and didn't even blush.