On the surface, Calvin Sperling appears to be just another federal bureaucrat, toiling away in his simple Beltsville office lined with gray filing cabinets and standard, government-issue metal bookshelves. Only the large world map behind his desk brightens an otherwise lackluster office.

But on a closer look at both the photo albums on the bookshelves and the dried plant specimens in the cabinets, a visitor might conclude that the mild-mannered U.S. Department of Agriculture employee is, in actuality, a tame version of Indiana Jones. Here is a bureaucrat who has traveled to many obscure places that are not mentioned even in the fine print on his large wall map, which serves as more than a mere decoration.

Like Jones, the 33-year-old Sperling trots the globe searching for long lost treasures. Also like Jones, Sperling is young, energetic and has had, as he says, his "share of snake stories."

The major difference, however (aside from the fact that there is no film crew following, or even creating, Sperling's exploits), is what the two are seeking. Jones is after long lost religious artifacts; Sperling searches for forgotten and soon to be extinct plants. What's more, Sperling is considerably more successful in bringing his findings home.

In eastern Kazakhstan in the U.S.S.R.,, toward the Chinese border, for example, Sperling traipsed over mountain slopes, searching for wild apricot trees. He had expected to find about 20 forgotten varieties. Instead he brought back nearly 50 different specimens. "I found some incredible ones, with traits we've never known before. They were yellow to nearly reddish, with some having perfectly smooth skin just like a plum. Some had a whitish green flesh; others, orange flesh dripping with juice."

In Uzbekistan, U.S.S.R., Sperling hiked through ravines and valleys to collect seeds of wild apples. In Turkey, he scoured fields and more mountain slopes looking for wild relatives of chickpeas. In two preserves in the forests and mountains of Ecuador, Sperling catalogued wild potatoes, currants, gooseberries, blueberries and blackberries, while in Peru he climbed treeless mountain slopes looking for wild relatives of Andean tuber crops not known in this country.

"I love plants and the diversity of plants," says Sperling, whose job is to rescue plant strains before they are lost, whether from development, disease, deforestation or just the simple fact that farmers no longer are growing them.

Sperling's goal is simple: Find bygone strains (or germ plasms as they are called in the business) that, when incorporated with new and contemporary hybrids, will produce higher yielding, better tasting and more disease resistant plants. It is a job, he says, that "consumers probably never think about. It's what goes on behind the scenes of the supermarket to assure a diverse supply of food."

"Genetic diversity is the key," Sperling explains. "There is a diversity of economic plants from alfalfa to zucchini. Some varieties keep better and store better than others. Some bake better than others. Some have higher levels of protein than others; some, lower levels of protein."

Despite his exotic travels, Sperling bristles at notion that he is the U.S. government's version of Indiana Jones. "It's rather unfounded to conjure up {such} images," the easy-going bureaucrat says brusquely. "For one thing, difficult situations don't occur if you have proper prior planning before an expedition -- and we try to."

What's more, he adds, "a lot of what we do is library work -- a lot of literature work. We also do a lot of collaborating with scientists in this country and foreign countries."

Even so, the job of a plant explorer often involves the unexpected, as well as adventure, notes Howard Scott Gentry, who as one of the country's most respected plant explorers worked for the USDA for 24 years until he retired in 1971. Now 87, Gentry likes to recall one of the earliest USDA plant explorers, Frank Meyer, who in the early part of this century, spent more than a decade traveling the Asian continent, crossing it by cart and on foot. "He finally went overboard in the Yangtze River. They picked up his body along the banks. They never could determine if he fell over, was pushed over or what."

Gentry, himself, remembers spending "a lot of time on foot and mule back, traveling in all sorts of conveyances and living a large share of the time over the campfire ... I've had my life threatened on a few occasions, {including} from opium growers in the Sierra Madre mountains of Mexico. They were suspicious of me since I wouldn't buy their products. They thought I was a spy. But that was incidental. I had a good guide and he talked to them so they let me go."

Gentry doesn't like to spend much time talking about these adventures, however, stopping himself short and saying simply, "I don't want to dwell on that aspect; it makes it too romantic. I just did my job and I probably was safer in the woods and out in nature than traveling on American highways."

Gentry would rather talk about the scores of plants he discovered that found their way into American horticulture. "I discovered the wild progenitor of the common bean in Mexico and Central America. I went looking for them in the wild and found them and made a number of collections that have proved to be very useful in breeding. Some of them have a natural resistance to city smog and some forms are resistant to bean weevil. So plant breeders have been incorporating these into our cultivated varieties which have larger beans and larger crops."

Meanwhile, a discovery of wild oats in Israel in the mid-'60s by another plant researcherr resulted in one of the most productive oat plants in the U.S. Similarly, peanut seeds, collected serendipitously in 1966 in Peru by an explorer who was searching for wild species of maize, have turned out to offer resistance to two important peanut diseases.

Other plant hunters have brought back wild strains of tomatoes from the Andes that have enabled that vegetable to be sold year round. "Some people won't say that that's good," acknowledges Henry Shands, who as USDA's national program leader for germ plasm, oversees the country's current collection of some 380,000 different seed varieties.

"But the fact that you can buy tomatoes 12 months a year and they do survive a long time in shipping and can get from California to the East Coast, that's an incredible thing," Shands says.

Compared to Gentry, Sperling is clearly a newcomer, having worked as plant exploration officer at the USDA's Agricultural Research Service for only three years. An economic botanist by training with a PhD from Harvard, he acquired his love of plants early in life. "I was born and raised on a small farm in central Minnesota. I despised farming but loved plants. I was always walking over the next hill to see what grew."

Now, Sperling not only is getting paid to walk over that next hill but he is coordinating the government's stepped up efforts for other scientists to make the march as well. Sperling's office has an annual expense budget of $207,000, which funds about 10 explorations a year, about a third of which are done by Sperling, the rest by other American scientists.

"The opportunities are becoming less and less as germ plasm disappears, as countryside is grazed by animals and development takes place," says Allan Stoner, research leader of the National Germplasm Resources and Sperling's boss. "So we've really got to get our act together to get this all very quickly."

After examining the gaps in the current germ plasm collection and identifying what new plants should be collected, Sperling contacts the foreign governments where these species are located.

"Sometimes we can get material just by asking; we don't need to send a collector," says Shands. But other times, the country may not have the specimen -- or may refuse to give it to U.S. officials without a fee. "They assert property rights on genetic resources, which means there are places where we are unable to get some."

Additionally, there are a number of areas where explorers just aren't welcome by foreign governments. For example, says Shands, in India "there are many crops of interest but they are in areas where there is intense guerrilla activities between the Sikhs and other factions. Those countries don't want to take the responsibility of having people go in and if they won't let you come in, there's nothing we can do."

Sperling himself makes about three trips a year, each lasting between three and five weeks. While much of his time is spent hiking over the fields, he has found it equally rewarding to spend time in local markets and, if lucky enough, in the homes of farmers and local residents, taking part in their native meals.

"It's helpful to know how plants are used and that's where the cuisine comes in," Sperling says. "If you have a knowledge of the end use of a product, you acquire clues as to their specific traits. For example, is the wheat better for making bulgur or bread?

Along the way, Sperling has encountered many culinary surprises. "A papaya we tasted seemed insipid but we found out that people cook it. Our first impression was you'd never cook papaya." Then there were the tree tomatoes in Ecuador. Sperling could never figure out why natives would want to use this somewhat bitter crop. But then, he had some in a cooked salsa, and immediately understood its attraction.

Of all his meals, perhaps the most memorable was the bread he and two Turkish scientists shared with a couple in southeast Turkey. They had come across the couple as they were harvesting one of the poorest and scraggliest crops of wheat Sperling had ever seen. "Their field was in extreme drought, a disaster. But they shared their lunch with us, offering us bread made from last year's harvest. It was the best bread we ever had."

Those are the memorable moments. There are many others that are not so notable. "You don't stay in the best hotels every night. Sometimes you pay less than $1 a night and you get what you pay for. There are long hours, lots of walking and lots of rough conditions."

Then there are the snake stories. Sperling shakes his head when he thinks about these but he repeatedly declines to talk about them. It's unclear whether that's because he doesn't want to relive the memories or rather, as he says, because he doesn't want to offend the host governments.

Of all of his findings to date, Sperling is most excited about the apricot cuttings and seeds that he carried back form Kazakhstan in his well worn piece of luggage. The plants now are in quarantine while USDA officials make sure they won't introduce any exotic pests or diseases to American stone crop production. If the plants are found free from disease, they will then be grown, studied and catalogued in the National Plant Germplasm System, available to public and private breeders who want to develop crossbreeds and hybrids.

"We hope these apricots will have traits that {when incorporated into existing crops} can extend the season, which right now is very narrow," Sperling notes. At the same time, Sperling's discovery of a wild, smooth-skinned apricot could result in a similar cultivated fruit here. "To get a smooth apricot, this country will go wild," says Shands. Still, both Shands and Sperling caution that this development could be at least 15 to 20 years away.

In the meantime, Sperling is getting ready to hunt for wild species of the walnut tree. He already found one in an apricot orchard in the Soviet Union. "The tree bore 50 percent more nuts per cluster than the typical walnut tree," he recalls proudly.

"There's a tremendous opportunity for new products or new varieties of products," says Sperling, who notes that the American consumer has become increasingly receptive to new and different types of produce. "Look at all the different colored peppers they are buying." Future products that might be commonly found at the supermarket may include red and yellow carrots, purple-skinned potatoes, burgundy beans and all sorts of different fresh herbs.

"All these things are available in some part of the world," says Sperling. "The sky's the limit."