dahlia: any of several plants of or developed from the species Dahlia pinnata having tuberous roots and showy rayed variously colored flower heads; native to the mountains of Mexico and Central America and Colombia
whole: an assemblage of parts that is regarded as a single entity
compositae: plants with heads composed of many florets: aster; daisy; dandelion; goldenrod; marigold; lettuces; ragweed; sunflower; thistle; zinnia