From its "North Star" motto to the "Land of Sky Blue Waters" advertising slogan, Minnesota has long linked itself to geography and nature. So, too, have the state's artists from the earliest days limned Minnesota's lakes and rivers, the bounty of its prairies and the people who populate them.

Given that deep appreciation of this place called Minnesota, there should be more to love in "Tenuous, Though Real," the Weisman Art Museum's summer show of work by more than 30 Minnesota-affiliated artists. Drawn from the museum's collection, it spans 150 years but concentrates primarily on recent decades.

The awkward title is an inadvertent tip-off to the unfocused ramble of the show itself. It comes from "Minnesota Painting and Sculpture From 1820 to 1914," a pioneering 1976 survey by the late Rena Neumann Coen, who taught art history at St. Cloud State University (and is the mother of filmmakers Joel and Ethan Coen). She asserted that the state's aesthetic was founded on "a tenuous, though real, sense of shared experience -- an identification, however fleeting, with the Minnesota scene." If that sounds like grasping at the proverbial straws, well, it was.

Most artists identify in some way with the scene around them, whatever it is, but the statement is meaningless unless that identification is apparent in the work. And if it is to matter, the art also needs the keenness of observation, technical facility and originality that signal greatness.

Few of the Weisman pieces meet that standard. Aside from Alexis Fournier and a few of his contemporaries, talented and well trained artists were rare in Minnesota's early days and the Weisman doesn't have their best work. There are some fine things among the more contemporary pieces, but the show is so thematically diffuse that individual pieces fade into the general miasma.

Land and water

Roughly half of the show is given to land-and-water motifs. The best of the early paintings is Jerome B. Thompson's 1870 "Minnehaha Falls," which captures the luminous sparkle of the tea-colored cascade. Clara Mairs' mawkish 1915 oil sketch of a Sunday painter at work is topped in awfulness only by Henriette Clopath's dreary "Cascade at Lutsen." The fact that Clopath (1862-1936) once taught in the University of Minnesota's Art Department says volumes about the state's slow development in the visual arts.

Lake Superior fares much better in "Hymn, Bloodstone Rising," a small but mesmerizing 1993 vista by George Morrison of a vast sunrise rendered in dancing pinpoint dots. Josephine Lutz Rollins captures the lake's brooding grandeur in a 1950 gouache while photographer Stuart Klipper frames its Encampment Island in a pale halo above an icy shoreline. Portrait photos by Katherine Turczan and Alec Soth, from his famous "Sleeping by the Mississippi" series, introduce the oddball characters sometimes associated with life on the water. Judy Onofrio's amusing "Big Catch" sculpture is a witty rejoinder to the serious stuff -- a 7-foot-tall assemblage of aquatic life (snakes, fish, eel) made from broken crockery, bottle caps, bones, shells and glittering detritus.

Next comes the land theme. Hazel Belvo's energetic 1986 drawing "Witch Tree Torso 23" memorializes a 400-year-old cedar that is sacred to the Ojibwe. Gary Hallman recorded nine shabby Minneapolis grain elevators in 1976, a tribute to the city's waning role in the international grain trade. In this context, Theresa Handy's abstract green/brown painting reads as a hymn to prairie grasses and plowed fields. Several earlier pictures haphazardly flesh out the theme.

Conceptual and figurative

More conceptual and figurative pieces fill the second half. The thematic high point is "Landscape of Hope and Despair," a poignant 1989 memoir -- in photos and prose -- of a failed Freeborn County farm by Linda Gammell and Sandra Menefee Taylor. Vesna Krezic Kittelson's vivacious cutout portraits of "Young Americans" sample the state's increasingly multi-ethnic population, while Laura E. Migliorino suggests its darker side in drawings inspired by the abduction and murder of a small-town Minnesota girl.

A couple of Paul Shambroom photos (police, Control Data workers) hang near a suite of Karl Bethke prints inspired by the Anglo-Zulu war of 1879, a David Rathman abstraction and two paintings by American Indian artists: Julie Buffalohead's quasi-autobiographical trickster picture and Jim Denomie's satirical "Attack on Fort Snelling Bar and Grill," in which mounted Indians descend on a White Castle as film cameras roll and nighthawks from an Edward Hopper painting sip coffee.

What is Weisman's aim?

The incoherence of this show is especially unsettling in light of the museum's potential.

With the opening in fall 2011 of its beautifully expanded galleries, the Weisman has a splendid facility at a perfect location overlooking the Mississippi River. As a teaching museum affiliated with Minnesota's leading university, it has an obligation to provide students and the larger community with a rich program of scholarly and appealing shows.

The high points of its collection -- exemplified by its Georgia O'Keeffe, Marsden Hartley and Charles Biederman paintings -- easily match the best of Walker Art Center and the Minneapolis Institute of Arts. It needs more art of that quality, smartly deployed in more stimulating shows. • 612-673-4431