The botanical genus Brassica comprises plants we commonly call leaf mustard, ornamental cabbage/kale broccoli, cauliflower, Brussels sprouts, canola and turnip. They are annuals (completing their life cycles within one year) time, including producing many small flowers with a cruciform shape, looking like Xs.
The perianth comprises the showy petals and protective sepals of the flower. Brassica plants bear four-petaled blossoms, and collectively all petals comprise the corolla. The sepals protect the flower bud, effectively being the four green leaves under the open petals. The sepals comprise the calyx.
The male-gendered flower parts make up the androecium. A Brassica blossom bears six stamens, each consisting of a thread like stem called a filament. Atop the filament rests an anther, the organ that produces pollen. The anther splits open to release the pollen grains to be gathered and transferred to other flowers by pollinating bees.
The female organs make up what botanists name the gynoecium. In the center of the Brassica flower lies an upright, tubular pistil--the ovary. At the tip of the pistil you find the stigma, a sticky receptacle where pollen rests after the bees drops it after a visit. The long neck of the pistil, the style, leads downward to the ovary at the pistil's base. Slightly swollen, the Brassica's ovary develops with two chambers, or ovules. The ovules become seeds after the pollen grains travel down the style to complete fertilization of the ovary.