Pansy

(Here's a specific example of a flower costume, with three different variations, the first of which is illustrated at left.)

Short white dress trimmed with deep rich-coloured violet pansies, one large one forming the head-dress the petals standing well round the head, like a brim; the bodice made of dark petunia velvet, arranged to simulate the flower, the soft peach crêpe de chine draped with pansies; a fan in the shape of a pansy.

Or, dress of amber-coloured soft silk, trimmed with purple bands, outlined with gold; loops of purple and amber-coloured ribbons on the top of the sleeves; head-dress in the shape of the flower; white bibbed apron, embroidered in purple; a gold basket of hearts-ease carried.

Or, dress of violet tulle and satin with profuse trimmings of the flower; wreath and shoes to correspond.

Source: Holt, Ardern.  Fancy Dresses Described, 5th Edition.  London: Debenham & Freebody, 1887.