Floating majestically in marshes of the Anacostia River are Cleopatra's favorite flowers, the lotus and Egyptian waterlilies of the Nile. Nearby in more than 50 other lagoons are the even more exquisitely beautiful day and night-blooming Asian and South American waterlilies.

Most are now in full bloom, enjoying the near tropical heat of a Washington August. But almost no one visits them. The Kenilworth Aquatic Gardens, one of America's major public water gardens, founded in 1882 and taken over by the National Park Service in 1938, has become one of the Washington area's least visited and most neglected parks.

Its entrance beside a public housing project, surrounded by a double-strand barbed wire fence and a treeless, weedy parking lot with broken lamps, the aquatic gardens has seen its staff and maintenace money dwindle over the past decades as the Park Service lavished attention and limited funds on Washington's popular, downtown parks.

Even the waterlilies themselves, which used to be catalogued and identified by signs, now simply float in magnificent mass confusion in 14 acres of ponds, leaving the park's few visitors amazed at the water wonderland but none the wiser about what they've seen.

The Park Service hopes to change this, however, at least some of it, by increasing the full-time staff next year from six men to eight - what it was in the 1960s, but far below the 28 full and part-time gardeners employed in earlier years - and by increasing the annual maintenance budget from the current $130,000 to $173,000.

"We also plan to put signs on the ponds and publish a brochure which will enable visitors to take self-guided tours," says Park Service spokesman George Berklacy. The increased funds are part of the President's Bicentennial land heritage program which this year alone is providing $96 million to upgrade maintenance in federal parks around the country, including $6.8 million for parks around the Nation's Capital. If Congress funds the entire $694 million requested by the President, Washington-area parks will receive a total of $60 million and about 60 additional park employees over the next four years.

Despite the run-down appearance of the Aquatic Gardens and the little publicity given it by the Park Service, almost 33,000 visitors found their way there during the Bicentennial, through a labyrinth of Anacostia streets off Kenilworth Avenue (I-295). Even that crowd estimate is questionable, however, since the park's limited staff spends most of its time not counting tourists but wading among the waterlilies in a constant struggle to keep the ponds clear of seaweed.

If the Park Service has had little money to improve the Aquatic Gardens it has at least preserved the lily ponds and marshes around them in relatively good condition and maintained much of the stock of tropical waterlilies it inherited from the daughter of Civil War veteran Walter B. Shaw, who began the gardens in 1882 as a hobby and then went commercial. At one time he sold as many as 1,000 cut flowers a day.

While there are many varieties of waterlily, "they're hybridizing themselves all the time," says Paul Souder, staff horticuluralist with the Park Service. "Our most famous is the East Indian lotus we germinated from ancient seeds here in 1951."

The seeds, unearthed in a Manchurian lake bed deposit and carbon dated as about 1,580 years old, germinated after their hard shell casings were broken by horticulturalists then working at the gardens. The lotus, Nelumbian nucifera, which has huge, but delicate pink blossoms, now flourishes both in a fenced pond and in the open marsh.

"Cleopatra liked these Egyptian lotus here," said Souder on a tour of the gardens, "but I prefer the Asian lotus. It has perhaps the best color of any flower I know. And it's fragrant."

Souder, who worked at the gardens when he first joined the Park Service in the 1950s and planted the half dozen bald cyprus that are now over 30 feet high, says the marshes still have most of the wildlife and plants they had in the last century. "There are still ospreys, muskrat, heron, native waterlilies and wild rice and lots of water snakes."

Site manager Freddie Lundy confirms the snakes. "I've been bitten seven times . . .but they're not poisonous and I never got bitten on a path, only when I was in the lily ponds raking seaweed."

The gardens are most beautiful in the early morning, since a few of the night bloomers are still open and the day-blooming lilies close up after noon. Like its neighbor across the Anacostia River, the National Arboretum, the Aquatic Gardens provided flowers and displays for several downtown parks. The Park Service fountain between the Jefferson Memorial and the 14th Street Bridge has day-blooming waterlilies as do several fountains around the Department of Interior at 19th and C Streets NW and local Park Service headquarters on Hains Point.

But they do not have thousands, including the Asian lotus and the Victoria waterlilies which have pads up to eight feet wide and can support a 100-pound person, though Park Service employees don't recommend it. Nor do they have the muskrats, hummingbirds, ospreys, wild rice and flowers in profusion - and watersnakes - that the Aquatic Gardens can boast.