Given Milton Avery's fondness for broad arabesques and liberated colors, it's no surprise that he felt completely at home with the medium of watercolor. Starting in his 40s, Avery (1885–1965) turned regularly to the medium when his oils were unavailable or inconvenient, and in his later years often combined it with opaque media such as crayon and pastel. Knoedler's selection, limited to the artist's pure watercolors, spans four decades with more than 30 works. These include many from the private collection of the artist's family that have never before been exhibited.

The watercolors' subjects are the still lifes, interiors, and landscapes familiar from his oil paintings, and they reflect the same trend toward increasing abstraction. With its elementary composition of gamboling shapes and colors, "Little House by Purple Sea" (1958), produced when the artist was in his 70s, is classic Avery. At once fanciful and resolute, it locates the essential aspects of a scene — a house perched on a shore, spreading water, a crowding background — with an elementary scheme of purples, blues, and greens. With the even more reductive "Edge of the Lake" (1953), Avery shows off more of watercolor's unique qualities with blended, layered, and dry-brushed strokes that build as bands of water, trees, and sky. Some of the later watercolors, animated by scratchy textures rather than a counterpoint of tones, seem more tentative in design, but even these resonate with the artist's appealing blend of obtuseness and grace.

Most surprising are works from the '30s. The very earliest cityscapes, naturalistic in color and modeling, appear to predate the artist's conversion to Modernism. But by the time Avery produced the striking "Drawbridge" (c. 1930s), he had begun to simplify and flatten, while still observing dramas of tone and texture; its fluid mixing of light and dark blue-greens wonderfully evoke overcast sky and reflecting water. The artist, moreover, exploits the tensions of shapes, conveying the drop from the parting black ramps of the bridge to the paper-white of a tugboat far below.

Another remarkable work from this period, "On the Boardwalk" (c. 1930), orchestrates a crowd scene with humorous verve. A large umbrella shelters a foreground couple from bits of humanity all around: at left, the lumpy curls of a sunbather, viewed through a railing; at right, a high-heeled foot, the vestige of a pedestrian striding off the paper; above, in a sea of faces, the startling aspect of a man staring at us, his tiny bow-tie echoing the umbrella's great sweep. In terms of wash technique, this watercolor is unambitious, even clumsy, but as a composition it brims with energy and insights.

Cornelia Foss's landscapes, too, radiate an enthusiasm for the observed. While Avery restlessly plies the territory between nature and abstraction, Ms. Foss sides conspicuously with nature, evoking the particularities of light in large landscapes of seashores and fields.

With rapid but controlled brushstrokes, Ms. Foss delineates rounding dunes or a wave's diagonal beneath a vast sky. In "Gray Day" (2007), the artist's sure grasp of color shows in the subtle beige of the beach, which, infinitesimally varied in warmer and cooler tones, neatly captures the effect of lightabsorbent sand on an overcast day. A handful of quick marks of midtoned blue perfectly describes a wave's white foam, shadowed by its own crest. As in most of these landscapes, however, the sky is the most substantial of all, with subtle but decisive shifts of colors imparting a complex depth.

Among a number of smaller landscapes, portraits, and flower paintings in the gallery's smaller room, "Tulips" (2007) stands out for its fiery reds and brilliant pinks. Where these vivacious petals turn toward shadow, colors poignantly express their constrained glow.

Though working far more naturalistically than Avery, Ms. Foss doesn't always lend as much pictorial gravity to her forms. The twisting diagonal of a seashore, and even the horizon itself, sometimes seem to be swept up in the overall bowl of space rather than measuring out its dimensions. A canvas such as "Gulls" (2007), however, beautifully establishes the proximate and the distant, the large and the small. Here, a plane of silvery water slips beneath the thick luminosity of sky, while slivers of deep blue and light beige hold the horizon. In front rises a flutter of small, varied darks — a flock of birds. Against the fullness of air and of water, their dense notes powerfully elicit the abundance of nature.

Avery until August 10 (19 E. 70th St., between Fifth and Madison avenues, 212-794-0550);

Foss until June 9 (210 Eleventh Ave., between 24th and 25th streets, 212-334-3400).

Graceful, mature, modest paintings full of light and a subtle geometry, Cornelia Foss's views of the beaches and salt marshes on Long Island and of Central Park convey a quiet awe for the beauty of nature and for paint's mellifluous ability to embody it.  Whether it's a vista through flowering bushes and beneath heaving branches across a summer meadow; or the dark blue sky pressing down on a flat field, with a turquoise pond, like a gem, sparkling in the middle distance; or the glow of the sun against snow, silhouetting a pine whose shadow frames and balances a barren tree in the foreground - the mood is calm, bright and alert.  Ms. Foss's touch is best when at its loosest, almost as if offhand, as in a couple of small portraits of children and in bigger pictures like "Spring Ride" and "Birds of Winter II," a tall panel of complex angles wherein a small flock of birds silently pecks at a pillow of white beneath a sheltering pine.

“What goes around comes around,” the old saying goes, and somehow we think it fits Cornelia Foss’ latest New York exhibit: arresting images of the four seasons. “I was not conscious of what I was doing,” Ms. Foss notes, “but this show, more than any others I have done, reflects my experiences during the past year.”

An example from the current exhibit at Manhattan’s DFN Gallery graces this week’s cover, called “Stormy Weather.” It’s not the picture one perceives of East Coast climate, however: waves crashing, a dark and dank atmosphere.

Ms. Foss gives us comfort with her view of inclement weather; there’s something calm about her painting, something uplifting and non-threatening that permeates the image.

“What goes around comes around” also applies as we experience Ms. Foss’ spring and summer images as well, their colors idealized yet realistic, her settings both ones that exist and ones that will come to exist.

The same saying rings true regarding Ms. Foss’ personal life. While she talks with sadness about the friends she has lost, you know that Ms. Foss’ optimistic demeanor will return, like the swallows to Capistrano. We have a sense that whatever small or large event may occur during a given period, it will be deeply felt by Ms. Foss. Yet she seems to have an intuitive sense of life’s ebbs and flows, responding accordingly.

Such response is not simply apparent in Ms. Foss’ overt behavior, but also in her aesthetic process. Consider the fact that she may paint beautiful summer scenes in the midst of a dreary New York winter, where her only view looks out onto a messy and wet Broadway. Ebbs and flows persist in her subjects, too: often intimate, at times distanced.

There are aspects of Ms. Foss’ life, however, that remain constant and do not change with the tide’s ebbs and flows or the principle of going around and returning. Those elements reflect what she likes and dislikes about people. Ms. Foss doesn’t hesitate when being specific: “I like individuals with a sense of humor, ability to have fun, who are generous, and above all, have a lively interest in all kinds of things.”

And what about feelings about her own life? Do they remain constant as well? You bet. “Mostly my life has been lucky,” Ms. Foss comments with fervor. “There’s nothing sadder than to do something you don’t want to do or not knowing how to go about getting what you want.”

Cornelia Foss...has been painting for more than 50 years and...has had close to 150 solo and group exhibitions throughout the United States as well as abroad.

When Ms. Foss was in her teens, her father was awarded a Prix de Rome by the American Academy in Rome; there she studied under the sculptor Mirko, receiving the First International Prize for sculpture at age 17.

As a young woman, she married Lukas Foss, moving with him to the coast when he was named professor of composition and conductor at the University of California at Los Angeles.

While in L.A., Ms. Foss attended the Kann Art Institute and made the switch from sculpting to painting.  She explains, "I was struggling a bit and at one point knocked off the nose of a figure I was working on.  It seemed to me that the people who were painting were having more fun."  Her first solo show of paintings at the age of 20 was in Los Angeles.

Ms. Foss is known for seascape and landscape oils featuring huge skies, "the result of personal feelings and a tradition long-established by Fairfield Porter and Jane Freilicher," she says.  "When you are out here, your first sensation is of the beauty of the vast sky and the smaller landscape in comparison."

Karen Wilkin, the critic and curator who authored the catalogue for Ms. Foss's recent show, wrote that "the surfaces of the paintings are cool, her touch, elegant, but at the same time, they are powerfully evocative of leaves, stone, sand, sky, and water."  Recalling her first encounter with Ms. Foss's paintings, Ms. Wilkin wrote: "I immediately felt great pleasure to be so taken with her work and convinced by its strength and sensitivity."

Like many artists, including Degas, Ms. Foss also paints from photographs, especially for commissioned portraits.  She explains that painting from a photograph is not better or worse than painting from real life. "It just produces a different kind of reality."  She continues, "All painting is a form of abstraction since what we paint is not a real thing.  Painting from a photograph is in a sense creating an abstraction from an abstraction."

Ms. Foss admires Vuillard, Picasso, Sargent and Whistler. Years before Lucien Freud was recognized, she identified him as a mentor.  As she says, "An artist like Freud influences you by giving ideas and showing a certain way of handling something which is new to you."

The Fosses have created an oasis far removed from the hectic pace of "the Hamptons."  At the time of the interview, Ms. Foss was looking forward to the rest of the summer, although she anticipated it would not be totally serene: as she pointed out, "I am already three portraits behind."