1. The mature flower of the soy bean consists of a calyx tube with five unequal lobes, five distinct petals, ten stamens (nine united and one free), and a single carpel. Both unicellular and multicellular trichomes are found on the calyx and pistil. 2. The flower primordium appears first as a protuberance in the axil of a bract. The order of emergence of the floral organs is sepals, petals, outer cycle of stamens, inner cycle of stamens, pistil. The order of emergence within each cycle is from the anterior to the posterior side of the receptacle. 3. Development of the petals is slow at first, but later becomes rapid. The stamens are free at first; later nine become united leaving one of the inner cycle free. 4. The one to four campylotropous ovules develop simultaneously, and the micropylar end is directed toward the distal end of the ovary.