This field guild shows 14 of the most commonly found wildflowers in the state of Missouri. They can be found in all regions of the state. Most flowers can be identified both by their inflorescences and their leaves, some of which are shown here. For a more complete guide to the flowers of Missouri, take a look at Missouri Wildflowers: A Field Guide to the Wildflowers of Missouri by Edgar Denison.
The Asteraceae family, also commonly called the daisy or aster family, is a large family of flowering plants. Flower is a general term for the reproductive part of a flowering plant. A flower usually consists of the stamen, which is a stalk where the pollen is produced, and carpels, which are hollow structures where ovules are produced. When a flower is pollinated, the pollen comes in contact with the ovules and produce seeds, which will eventually grow into a new plant. What identifies daisies is that flowers are arranged in inflorescences. Inflorescences are tightly packed groups of individual flowers. What is commonly considered the flower of a daisy, with long petals and a disk in the center, is actually the inflorescence. The disk in the center is actually a grouping of many individual flowers, each with their own stamen and ovules. Because of this, Asteraceae are sometimes called composites. The small flowers are often referred to as florets. Underneath the inflorescences are leafy structures called bracts, which protect the flowers before they bloom. Surrounding the disk florets are ray florets, which appear similar to the petals of other flowers, but are actually individual flowers. Because of the large variety of species in the daisy family, there are many different structures of inflorescence seen in asters. Inflorescences range in size from miniscule in diameter to more than 8 inches across in sunflowers. Some species, such as the bull thistle, have large bracts relative to the inflorescence that make up the flower head.
Because of the large variety of species of aster, identifying between similar species can be difficult. Common identifying factors are color and the arrangement of the both the disk florets and the ray florets. Although there are many similar species of daisy, leaf structures can be used to further differentiate between species with similar inflorescences. Many Asteraceae have leaves that or opposite near the base of the stem but become alternate closer to the top. The large number of similar species has led to the term “damned yellow composite” to describe the large number of yellow asters which are difficult to differentiate.
With over 23,000 individual species, the daisy family is one of the largest plant families in nature. In Missouri, it is the largest broadleaf plant family. With such size comes great diversity, and although most asters are herbaceous plants, the family also encompasses some trees and shrubs. Because of the large variety of species of daisies, they are found all over the planet, but typically prefer arid or semi arid regions. They are commonly found in many different regions of Missouri. Even thought ecology of Missouri has changed greatly in the last few centuries, species in the aster family are still very common, and many can be found thriving along roadsides and in urban areas. Asters are also grown commercially for herbal and medicinal purposes.