Consuelo Castiglioni is a case study in Milanese fashion. In a city where so many lines scramble to latch on to every passing trend, she has steadily progressed from the margins to a position of influence—like Miuccia Prada before her—by staying true to herself. We all know what "Marni-esque" means: It's shorthand for a guilelessly studied assemblage of fifties and sixties prints and anti-fitted shapes, which are now copied all over the place.

For spring, the Marni pieces we expect were there: the short, wide raglan-sleeve fifties jackets, the loosely fitted summer dresses, the duster coats pulled in with belts—all made with that familiar air of happy accidents at the home sewing machine. This season, the offbeat colors—ochre, ecru, salmon, emerald, charcoal, violet, pimento, and washes of blue—were drawn from Castiglioni's modern art studies (she cites Yves Klein, Robert Rauschenberg, Ross Bleckner, and Ugo Rondinone). But it's her odd eye for an accessory that's now coming through strongest. The quirky mix of patent leather, string, resin discs, plastic plaques, big clunky buckles, and foil sequins worked into belts, bags, and jewelry adds something completely new to a look that now has fans shopping in hordes.