THE ART of Stephen Tanis is on the verge of bursting into full bloom in his new show at Jane Haslem Gallery.

A gifted realist, Tanis settled on his signature subject long ago: A table--or occasionally a chair--draped with great swaths of cloth of varying texture and design. Working in oil, he scrutinized his draped objects with the eye of a traditional still-life painter, lavishing his efforts solely upon capturing surface light and textural effects.

Sometimes he added objects to his tabletops, or introduced a figure into the scene. But, at heart, these remained paintings about painting, with success depending entirely upon technical bravura. There was one significant stab at expanded content in the last show: a work titled "Kuniyoshi with Chair," which was, in fact, a painting-within-a-painting. In it a work by Kuniyoshi was depicted over an empty, draped chair, rousing not only a sense of human presence but a new touch of mystery and ambiguity.

The subject of paintings-within-paintings has been pursued in the current show, and the result is work that moves from still life into the larger category of interior view. By happy coincidence, there has also developed a new authority in the brushwork, a greater mastery of color and a lighter, more sensuous palette of pastels--pink, turquoise and yellow--that make the new work richer in every way.

A prime example is "Cynthia and Kuniyoshi," which reaches new heights of sophistication in its portrayal of an Oriental woman in a luscious pale violet kimono, seated before a painting by Kuniyoshi. But it is "Bierstadt and Amaryllis" that best illustrates how far Tanis has come. He returns here to the theme of a table swathed in drapery, but has combined it with a replay of a landscape by Albert Bierstadt that is ravishing in its virtuosity.

These works continue to be about painting itself, but are now also about art, adding a new dimension. It is no wonder that several of these works were snapped up before they ever reached the gallery walls. The show continues at 406 Seventh St. NW through Feb. 5. Hours are 11 to 4, Tuesdays through Saturdays. Margarida Kendall at Osuna

Margarida Kendall's surrealist fantasies come straight out of her imagination, but in recent years they have dealt increasingly with real questions of human survival. The subject of her current show at Osuna Gallery is of typically epic proportions--nothing less than the history of the world, from its beginning to its impending end. Incredibly, she manages to handle the matter with power and poignancy in only 12 small drawings, collectively titled "The City: A Poem."

She begins with "On the First Day the Creator Fled," spinning out her version of the Creation in a drawing of tall buildings and spore-like forms surrounded by a border of running horses, representing the deserting deity. Things don't go badly in her mysterious world until the seventh day, when some mysterious "adversary" opens a door no one can shut--an allusion, one suspects, to the atom bomb. Such suspicions are soon confirmed, as the wind stops and the mushroom cloud rises.

Since this is a visual poem, it is unfair to intercept its meaning with words. Let it suffice to say that while Kendall's small paintings and altar-like triptychs have always been impressive, her imagination has never been more fertile than it is here. The Lisbon-born artist will show next in a retrospective at the Gulbenkian Foundation in Portugal in early 1984. This show continues through Feb. 11 at 406 Seventh St. NW. Hours are 11 to 6, Tuesdays through Saturdays. Prints at Nyangoma's

Nyangoma's Gallery, which specializes in contemporary Afro-American art, is showing 16 prints from the Brandywine Graphic Workshop in Philadelphia, a nonprofit, community-based organization where young artists, black and white, have been learning the art and craft of silkscreen and offset printing in a workshop setting for more than a decade.

Washington artist Sam Gilliam is one of several artist-fellows invited to share his expertise at Brandywine, and he selected this show from the work of other artist-fellows. There are a few of Gilliam's own prints--not the most exciting he has made--along with silkscreens by well-known Chicago sculptor Richard Hunt, who has made vigorous but predictable images in the tradition of the sculptor's drawing. But Phyllis Thompson of Chicago has put the silkscreen medium to better use in her syncopated, spotted overlays of color, titled "Carrot Cakewalk."

The big treat, however, is the gallery of prints by Philadelphian John Dowell, who has been too long absent from the Washington scene. Inspired by the musical scores of John Coltrane, Dowell makes spare, rhythmic, calligraphic forms that dance across the paper, the only complaint being his faint-hearted use of color.

Master printer Allan Edmunds has produced a handsome offset poster for the show ($25), which also includes some swirling pastel abstractions by Washingtonian David Stephens. The show continues through Feb. 19 at 2335 18th St. NW. Hours are noon to 6, Tuesdays through Saturdays.