Botany: The Seven Most Common Plant Families, part 7: The Aster Family and Composite Flowers



“Many of the most beautiful of the autumn flowers belong to the Compositae, a family of such complicated flower arrangement that it is very difficult for the child or the beginner in botany to comprehend it; and yet, when once understood, the composite scheme is very simple and beautiful, and is repeated over and over in flowers of very different appearance……The large garden sunflower is the teacher’s ally to illustrate to the children the story of the composites.” -Anna Comstock, Handbook of Nature Study, page 574


The Aster family is the last stop on our quest to learn the seven most common plant families. This family is also sometimes called the Sunflower family. Asters are a composite flower which means that one flowerhead is composed of many smaller flowers. The smaller flowers are really five fused petals surrounding a pistil and stamens. The petals surrounding the disc are called Ray Flowers and these are each are a complete flower as well. Each tiny flower produces its own seed. 

"Can you see that what you call the flower consists of many flowers set together like a beautiful mosaic? Those at the center are called disc flowers; those around the edges ray flowers."-Anna Comstock, Handbook of Nature Study, page 503
(Botany studies,2008.)
Some other common flowers in the Aster/Sunflower family include Black-eyed Susan, Asters, Dandelion, Marigolds, Zinnia, Chamomile, and Chrysanthemums. They are all easy to spot because of their distinctive shape.

"Many plants have their flowers set close together and thus make a mass of color, like the geraniums or the clovers. But there are other plants where there are different kinds of flowers in one head, those at the center doing a certain kind of work for the production of seed, and those around the edges doing another kind of work." 
-Anna Comstock, Handbook of Nature Study, page 503


If you examine them and you can actually see the tiny individual flowers in the center disc, along with the Ray flowers protruding petal like from the outside. The interesting thing about the Dandelion is that it is a composite flower, but it is unique in that it is all ray flowers and does not have the center of disk flowers. 


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