On February 14, only one flower will do. It's not that a big bouquet isn't sublime, but a single genus best conveys a message of love: the rose, preferably in lush tones of red and pink. Although long stems crowd every florist's cooler, any romantic knows that beautiful blossoms are the heart of the matter -- especially when their stems are cut short and they're gathered into tiny vases or glasses arranged in the unmistakable shape of affection.