Joseph Elmer Yoakum

Through July 26. Venus Over Manhattan, 980 Madison Avenue, Manhattan; 212-980-0700, venusovermanhattan.com.

The visionary landscapist Joseph Elmer Yoakum (1888-1972) has been categorized as an outsider, self-taught or folk artist. Whichever: His place in the expanding canon of 20th-century American art is assured, both for his achievement and influence. The latest evidence of Yoakum’s originality is this enthralling exhibition, among the largest ever devoted to his work. It features nearly 70 of the artist’s delirious vistas of undulant hills, mountains and rock formations, variously striated, patterned and creviced, rendered in pale browns and pastels of colored pencil burnished to resemble watercolor. Defined by double outlines, Yoakum’s geological elements have a curious autonomy: They heave, lean and push against one another, but they also evoke soft creased flesh, voluptuous but slightly abstracted. Sudden breaks in the terrain offer views of tiny trees, distorting space and scale and intensifying the sexual undercurrent.

A magnetic ambiguity prevails. In “Mt Horseback on Rockey Knob Range Near Chillicothe, Ohio” (1969), tan flowing forms divide the scene like irregular columns. They could be landslides, or an alternate universe alive with writhing snakes and worms.

Yoakum concocted his fantastical topographies in a storefront on the South Side of Chicago during the last decade of his life, after years spent traveling the world as an itinerant worker. Once discovered, his art exerted an essential influence on Chicago Imagists like Jim Nutt, Roger Brown and Christina Ramberg. Beginning in 1968, he had several exhibitions in Chicago; one at the Whitney Museum in New York opened in late 1972, just weeks before he died on Christmas Day. ROBERTA SMITH