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Thursday, July 28, 2011

Prairie Spotlight: The Asters

It could be argued that asters are the most successful plants in the world. The family named for them, the Asteraceae, is the largest plant family (with nearly 23,000 species!), and contains many familiar wildflowers. Also called the Sunflower Family, the Compositae, or composites, the members of the family are united in having “flowers” that are really inflorescences composed of many small flowers. 

What we perceive to be petals are the ray flowers, in which five petals are fused to make a single ray on a very asymmetric flower. The interior of the “flower” consists of symmetric disc flowers that have five very small, inconspicuous petals (can you find them in the picture below?  Look around the spikey disc flowers for the five petals). 

Some composites, like the common dandelion, have only ray flowers, and others, like pussytoes, have only disc flowers. 

It’s relatively easy to see the many small flowers that make up a sunflower. The disk flowers mature from the outside toward the center.

It should come as no surprise that Asteraceae is well represented in the Laramie Basin, and is the best represented plant family on the Berry Prairie. Growing on the Berry Prairie and currently flowering in the wild are:

Antennaria parvifolia (Pussytoes)

Erigeron pinnatisectus (Featherleaf fleabane)

 Erigeron speciosus (Showy fleabane)

Gaillardia aristata (Blanket flower)

Tetraneuris acaulis (Perky Sue)

Several common shrubs, including sagebrush, rabbitbrush and winterfat, are also composites, though they look nothing like asters. We’ll have another blog about them in the future.

Written and photos by Dorothy Tuthill, Berry Center

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