Susan Crowder's "Aberdeen Landscapes," at the B.R. Kornblatt Gallery, 406 Seventh St. NW., are strong, stark and convincing. Though drawn in black and white--from memory, not photographs--they somehow seem more accurate than focused color slides. No details diminish them. The simple things they show us--a low and light-filled sky, stacked bales of fresh hay, the stubble of the field, dark trees in the distance--have been reinforced by summary. To see that Scottish landscape in these modest charcoal drawings is to know its look in life.

She has got the light just right. In evening, in high summer in that northern land, sunsets last for hours. And then, after the sun is down, the long twilight lingers. Birds stop singing, colors dim, until at last the fading light somehow seems to come from everywhere at once.

These drawings suggest colors. Their skies are uninflected white, the flat white of the paper, and yet Crowder lets us see the green-and-gray-and-silver moisture of the air. It recently has rained. The rain has smoothed and rounded the edges of the bales. With charcoal and eraser, she intimates as well the landscape's many greens, the yellow-green of drying hay, the deeper green of summer leaves, and the color, between those two, of fields not yet cut.

No workers, no machines, interrupt these images, and yet we feel their presence. Farmers drove those fence posts into the hard ground, and built those sagging stacks. At times they look like monuments, like so many standing stones made of baled hay. Crowder, a New York artist, lives not far from Sleepy Hollow. She also sculpts. The smooth stone pieces she is showing--they look like piles of sacks or pillows, or like neatly folded marble quilts--enhance her cleansing show. It closes March 23. William Dunlap at Gallery 4

William Dunlap fights the facile. He paints the sort of pictures--of rolling hills, weathered barns and cows in snowy fields--viewers mine for sweet nostalgia. Dunlap will not let them. He fights them all the way. His landscapes are on view at Gallery 4, 115 South Columbus St., Alexandria. They do not soothe. They bite.

Dunlap was born in Mississippi and has lived in Appalachia. Though he paints a land he knows and loves, he has to be aware that the Wyeths and their minions have ruined barns and grazing cows. They have made such things cliche's.

The viewer who applauds Dunlap for portraying every blade of grass finds, as he looks closer, that the grass is filled with clutter, with letters, numbers, arrows and dots that should not be there at all. Dunlap's art looks "realistic," but he undercuts that, too. Dunlap does his sketches on sheets of blue-ruled paper torn out of school notebooks. It seems that he has taped those sketches to his pictures, but they're not taped down, they're painted there, complete with painted shadows, painted blue lines, painted tape. Those jottings look more "real" than the rolling hills beyond.

Dunlap wants the viewer not to smile, but to cringe. A stag's head severed at the neck is an image that recurs throughout his exhibition. Blood soaks into snow. While he skillfully portrays barns, cows, snowy skies, those overly familiar props of agrarian sentimentality, he won't let us forget the old violence of our land. His show will run through March. Skunder Boghossian at Nyangoma

Skunder Boghossian also summons in his art the spirits of his land. Or, rather, of his lands. Though raised in Ethiopia, he has taught since 1971 at Howard University, and his moving, heart-felt pictures mix the American with the African, the observed with the imagined, the ancient with the new. They are now at Nyangoma's Gallery, 2335 18th St. NW.

A narrow strip of parchment, a sort of unrolled scroll, half picture, half epistle, is an image he repeats. A number of such parchments--bearing painted images of warriors, saints and angels, lizards, lovers, birds and signs one cannot read--hang in stiff translucence before the gallery's bay window. Many more are portrayed in the pictures on the walls.

Read from top to bottom, or from heaven to earth, they half-tell complex stories of Christ and of His church, of animals and ghosts and strange sequenced designs. Skunder calls one bark picture "Rhythm Walk." A kind of visual dancing is felt throughout his show.

It is those scrolls that catch the eye, but what one sees behind them--the starry sky, the landscape--seems equally important. In one picture, the background conjures the houses, the movements and the shadows-upon-shadows of an Ethiopian village. There is a picture on the opposite wall--of the twinkling lights and towers of Manhattan--made just after the painter took his children to the Statue of Liberty. Those two handsome paintings, one flavored by New York, one by Africa, do not clash at all. Skunder's brushwork is free and sure, his colors are alive. His show closes March 19.