AMERICAN ART -- "Recent Trends in Collecting 20th-Century Painting and Sculpture from the NMAA," 100 works, opens Friday, continuing through March 21; "Egypt: Day and Night, Watercolors by Keith Achepohl," 35 abstract works opens Friday, continuing through April 4. "Recent Acquisitions: Prints Drawings and Watercolors." 60 works on pper, through May 16. "Roosevelt's America: New Deal Paintings from the NMAA," to commemorate the 100th anniversary of FDR's birth, continuing indefinitely. "A Life in Art: Alma Thomas, 1891-1978," 47 paintings, sculptures and works on paper, through Feb. 22. Eighth and G Streets NW. Daily, 10-5:30.

NATURAL HISTORY -- "Orchid Paintings by Regina O. Hughes," in the Rotunda Gallery, opens Saturday, continuing through April 11. "Dinosaurs and Other Reptiles" (Phase II of Fossils: The History of Life), new permanent hall includes a huge flying reptile with a 40-foot wing span, suspended from the ceiling, dinosaur reconstructions, clips from sci-fi movies. "Deep Sea Dives to Biological Frontiers," sample animals that live in geothermal springs, large scale model of the Alvin, Navy researcher submersible. World's first living coral reef exhibit. The Conquest of Land, showing the emergence of plant and animal life more than 400 million years ago. Tenth Street and Constitution Avenue NW. Daily, 10-5:30.

PHILLIPS COLLECTION -- "John Walker: Recent Works," 20 paintings by the British artist, opens Saturday, continuing through April 11. Paintings by Paul Klee, on indefinite display. Permanent collection includes masterworks of the 19th and 20th centuries. 1600 21st Street NW. Tues.-Sat., 10-5; Sun., 2-7.