A rose is a rose is a rose to Gertrude Stein, but not to Kevin Hoskins. At San Francisco's Salon des Parfums, a request for the flower—or the scent of one—proves far more complicated. "What kind of rose?" presses the 29-year-old shop owner. "Peppery? Floral? Green? Chocolaty?" Tucked away in a downtown high-rise, this celadon-painted store with red silk draperies is the exclusive U.S. outpost of the French perfume house Henry Jacques. Hoskins helps clients select—from the line's some 2,200 scents—the one that strikes a chord. Every scent is concocted from raw ingredients such as saffron, myrrh, and the exotic essence of o'od, from the Southeast Asian agar tree (only a few ounces are extracted each year). The fragrances start at $425 for a half ounce and reach up to $105,000 for 30 ounces in a Baccarat flacon. At 210 Post St.; 415-982-1500.