THE unknown 18th-century artist did the obvious. Below the 12 tranquil figures, all brightly clothed and comfortably positioned in an idealized Mexican landscape of palm trees, flowers, and a lake, he identified their races and numbered the figures. On the canvas. Below their feet.
This is the delightful introductory painting to ''Mexico: A Landscape Revisited,'' a resonant, dynamic, bilingual exhibition at the Worcester (Mass.) Art Museum. Culled from private and public collections in Mexico, the exhibit brings together some 50 paintings tracing the vitality of 200 years of Mexican landscape art.
Known as a ''caste painting,'' the introductory work served as a quasi-document of racial differences at a time in Mexico in which regionalism and political conflict flourished. In the churning, races were separating and mixing.
The landscape in the painting is idealized. Although speculation continues as to the exact reason for caste paintings, the artists may have borrowed labeling techniques from the many scientific expeditions of the time identifying new flora and fauna in Latin America.
But in Mexico, landowners were more interested in land than in landscapes or the races of indentured workers. The big haciendas resisted the rise of peasant discontent until the Mexican Revolution (1910-1920) upended the politics of the country, and land reform followed.
Up to that point, landscape art -- practiced by only a few Mexican artists, usually trained in Europe -- was detailed and representational, more an observation of nature rather than an interpretation. Or the landscape served as a mere background for religious paintings.
But the revolution encouraged expressions of a new Mexican identity free of European influences. The well-known Mexican mural movement, with socialist-realistic themes, helped define this new Mexican identity. Part of the national identity was also realized in the strong link between Mexicans and their land.
At the center of Mexico is a great, high plateau. Mountain chains lie on the east and west, and beyond these are lowlands fading into shorelines. Volcanoes, deserts, and two peninsulas -- Baja California and Yucatan -- are part of the geography. Artists in the exhibition have roamed throughout Mexico capturing ''la suave patria'' -- the beloved land.
Of the earlier paintings, ''Hacienda of Colon,'' by Eugenio Landesio (1810-1879), is a sunny, romantic, and warm view of a grand hacienda. But here the buildings are placed in the context of a vast, sweeping landscape.
Not until ''Landscape with Iztaccihuatl'' by Geraldo Murillo (1875-1964), known as ''Dr. Atl'' (a native word for water), is the Mexican landscape wholly interpreted as a subject, exclusive of haciendas, working peasants, or men on horseback. Dr. Atl is considered the first ''modern'' landscape painter in Mexico.
Husky and rough with swirling clouds and jutting mountains, Dr. Atl's landscape, painted in 1932, is part impressionistic, part El Greco with more texture, and painted with deep greens and blues.
In contrast, the dark majesty of Rufino Tamayo's (1899-1991) ''Mountain Landscape,'' is an abstract clustering of brown shapes glopped with little protruding knuckles and scratches of paint suggesting impenetrable, arid canyons cut by murky rivers. In this work, painted in 1961, is the essence of Tamayo's Mexico, an earthy, strange, and turbulent land, not to be seen literally but shaped by the mind's eye.
Tamayo, his international reputation built on the distinct Mexican nature of his work, was critical of the famed Mexican muralists for being too concerned with imagery. Tamayo's priority was to infuse his work with an indigenous quality. ''My ideas are purely plastic, but I am no different than other men,'' he said in 1966, hoping to bring his imagination to the lives of average Mexicans.
In contrast to abstract landscapes and sweeping vistas in the exhibition, the work of contemporary painter Mari Jose Martin depicts a lone cactus in ''The Light of Each Afternoon.''
Largely self-taught, Martin paints a jagged cactus in a vibrant landscape. The effect is like a pop to the eye. Blend hot red, yellow, and pulsing blue sky, and the big green cactus in the desert bursts into life as the dominant shape, an expression of essence rather than a detailed rendering.
Combining abstraction, detail, and rich, earthy colors in ''Two Chairs, Trees and Plants,'' Sylvia Ordonez's contemporary composition is a lush, dense landscape of improbable foliage and trees. Two chairs poking out of the greenery add a touch of Surrealism with echoes of Primitivism.
As an enriching complement to the exhibit, a portfolio of photographs taken in the central highlands and near Mexico City by Paul Strand and other photographers in 1932-33 is presented in a nearby room. Included is a stunning black-and-white photo by Fior Garduno of a girl standing in a Guatemalan doorway with an basket of fresh flowers on her head.
In another room is a small collection of Mexican lithographs including works of Diego Rivera, Jose Clemente Orozco, and David Alfaro Siqueros, considered the ''big three'' of the Mexican mural movement.
*'Mexico: A Landscape Revisited,' is on view at the Worcester Art Museum in Worcester, Mass., through April 23; the Laguna Gloria Museum in Austin, Texas, from May 1 to July 2; the Tucson Museum of Art from July 21 to Sept. 17; and the Memphis Museum of Art from Oct. 7 through Dec. 3.