Georgia O'Keeffe, Arthur Dove, Charles Demuth and Max Weber are among the artists represented in "Late Nineteenth Century and Early Modernist American Art: Selections from the Baker/Pisano Collection," but don't get too excited. The big names on the labels in this mediocre show--now at the art gallery of the University of Maryland, College Park--are often more impressive than the works of art themselves.

This is a show of leavings--of preliminary studies, demonstration pieces, casual experiments, pages torn from sketch books, and friendly little pictures quickly done for friends. Ronald Pisano and D. Frederick Baker, who assembled this collection in the past decade, are up on their art history. The oft-told story their collection tells--about the growth of modern painting in America from the art-for-art's-sake virtuosities of William Merritt Chase to the hard-edge images of Charles Sheeler and Ralston Crawford--is certainly important. But these pictures aren't.

"Moonlight" (1921) by the Tonalist Dwight Tryon (1849-1925) is an experimental landscape that looks as if it were painted with a sponge. Abbott H. Thayer's "View of Dublin Pond, New Hampshire" (1900) calls finger painting to mind. Thomas W. Dewing, whose genteel images of women are usually exquisite, was at first dissatisfied with the little reworked pastel sketch that represents him here; it's easy to see why. Max Weber's "Seated Figure" (1912) is a thick-thighed little nude suffering what seems to be a badly broken elbow. O'Keeffe's "Machu Picchu, Perua" (1956) is a hasty watercolor sketch as are Charles Demuth's "Old Top" and Arthur Dove's "Sunrise" (1941).

This show includes a number of entertaining oddities. Paul Manship, the sculptor, is represented by a pair of gilded candelabra on one of which an elf in shorts plays panpipes for a trio of attentive Pekingese dogs. "The Reception" by George Bellows is a picture of a party: One of the guests attending wears a tail coat and top hat; others, and the servants too, are completely nude.

A sort of inverse rule seems to guide the quality of this mixed collection: The better known the artist, the worse his works of art. Oscar Bluemner's little "Landscape" (1922) is full of mystery and power. Warren Wheelock's "Tobacco Jar" (1922) is both stylish and strange. Two women painters, both of whom were married to famous artists--Marguerite (Mrs. William) Zorach and Helen Torr (who married Arthur Dove)--are strongly represented. Both little bronzes by Alice Morgan Wright are also nice.

Not all the objects here are weak. Ralston Crawford's "Boxcar" (1941), Arthur B. Carles' fauve "Nude with Red Hair" (1925), Abraham Walkowitz's "City Abstraction" (1915) and that plump, dead fish that William Merritt Chase painted in the classroom as a demonstration for his students, are moderately distinguished. But almost all these artists are better represented in Washington's museums.

The show was organized by the Heckscher Museum, Huntington, N.Y. All the pictures in its catalogue, for reasons unexplained, are a shade of greenish-gray. The exhibition closes Oct. 16.