John Walker's Maine is a fertile place. It continues to provide rich source material for his work as he enters his fifth decade as a painter. Working in the studio or en plein air at the edge of an ocean cove (whose mud is sometimes incorporated into his paintings), the English-born artist, 71, does not offer scenic views of Maine. Instead, the landscape suggests to him motifs or structures, around which he builds essentially abstract compositions.

This exhibition featured seven small, five medium-size and two enormous canvases, all painted in 2010. Motifs from Walker's earlier series flow in and out of the recent work. The mud reappears, as do cutout shapes of painted canvas collaged onto the surfaces.

As in previous works, he peppers the grounds with flecks and smears of paint that convey the pebbled texture of a coastal flat at low tide. And recurring in some pieces is Walker's signature "alba" shape, initially inspired by the outline of the figure in black in Goya's Duchess of Alba (1797), who memorably points to the ground where the artist's name appears written in the sand.

In the small and medium-size paint- ings, which are accomplished works of sumptuous color and texture, we find Walker well within his comfort zone. His familiar forms, representing a cove, a tree or a brush fire, are simplified into archetypal symbols that he arranges in wonderfully improvised-looking composi- tions. One work, Coastal Cross, betrays the influence of Georgia O'Keeffe, and even more strongly implies a meditation on the most famously self-styled "painter from Maine," Marsden Hartley.

In the two largest paintings we see Walker stretching, pushing himself forward with new ideas and renewed ambition. The results are mixed, but nonetheless com- pelling. Bird Strike (about 8 by 13 feet) has lumpy, calligraphic tracks crossing a white ground; it brings to mind Rauschenberg's Automobile Tire Print (1953) and also Franz Kline. Walker's painting, however, could just as easily allude to a fallen tree or woody vines. At the lower center right of the canvas are summarily painted birds Black-capped Chickadees, the state bird of Maine. The other large work is untitled (9 by 10 feet) and has a thick area of mud in the center, which resembles a large cartoonish head. The shape brings to mind the schematic heads in late Guston, or a Ray Johnson bunny. Unique to this exhibition are the collaged newspaper strips that run off the edge of the canvas like streamers. Irregular patterns of white horizontal stripes and red Xs in thin and drippy paint, which look like chain-link fencing, cover large areas of the composition. This is also the only work on view that contains text. "Not now/ maybe never," scraped out of the white paint in the upper left corner, could refer to the artist's own apprehension with regard to the new directions and lofty goals he has set for himself in this show.

Photo: John Walker: Untitled, 2010, oil with mixed mediums and collage on canvas, 108 by 120 inches; at Knoedler.