Tag Archives: Asteraceae

Dandelion Flowers

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L- Common Dandelion plant R-Atypical Dandelion flower

L- Common Dandelion plant R-Atypical Dandelion flower lacking ligules

Common Dandelion (Taraxacum officinale) is a European species that is naturalized in Michigan. First recorded in the wild in 1837 when it was already well established. Brought here by the earliest settlers as a winter source of greens high in vitamin C they were eaten in the winter and early spring to prevent scurvy. The specific name officinale means “of the shops” and alludes to this useful plants value as a cash crop.

L- Dandelion flower head R- Dandelion seed head

L- Dandelion flower head R- Dandelion seed head

Dandelions are distinctive when in flower or seed. Be careful if you gather plants for greens. They are best when just coming up before they flower. Their deeply toothed leaves and milky juice help to distinguish them but there are look-a-likes. And of course never gather greens from lawns that have had chemicals sprayed on them.

L-Sectioned Dandelion seed head R- Ray floret with parts labeled

L-Sectioned Dandelion seed head R- Ray floret with parts labeled

What most people call a Dandelion flower is actually a many flowered head. This is true of all members of the large Aster (Asteraceae) family. At the base of a Dandelion head is a group of green bracts called the involucre. Dandelions have only one type of flowers, ray florets. Some members of the Aster family, for example daisies, have ray and disk florets. Ligules are the “petals” of the dandelion flower. Rarely you will find Dandelions where they are absent. The fuzzy ring at the base of an individual flower is the pappus. This develops into the feather-like structure of the seed. Pappus characteristics are needed to separate some species in this family. The involucre is composed of the phyllaries which are the green bracts under the flowers. The florets are held in the receptacle. See Brian Johnston’s post on Microscopy-UK for more photos including some great microscopic images.

Go outside, pick a dandelion flower head, and take it apart. Look at the tiny flowers under a magnifying glass. Try to find the pappus. Understand the structure of this flower head as a first step to learning about the fascinating Aster Family.
Copyright 2015 by Donald Drife

Webpage Michigan Nature Guy
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Coltsfoot: a potential invasive species?

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Tussilago farfara flowers

Coltsfoot flowers

Coltsfoot (Tussilago farfara) is a Eurasian species first collected in Michigan in 1840 (See Michigan Flora Online). I saw it for the first time on, March 15th 1978, in Bald Mountain Recreation Area and then along a road in Jackson County about a week later. I wondered if the plant was invading our natural areas, but almost three decades passed before I saw the plant again. I found a small colony in Crawford County in 2006 and that same year I saw 75 plants in Oakland County at Cummingston Park, in Royal Oak, Michigan. The Cummingston Park patch was wiped out when the pond was enlarged.

Tussilago farfara

Coltsfoot flower and seeds

In 2009, the Crawford County station was in flower on May 2nd. Two weeks earlier it was still covered by winter snow. By May 16th the leaves were developing and it was in seed by May 30th. In 2006, the Crawford County station was about 1 meter (3 feet) square. It has since increased to 1 x 2 meter (3×6 feet).

Tussilago farfara leaves

Coltsfoot leaves

The species might be overlooked especially in northern Michigan because it flowers early. It is currently (May 8th) flowering at the Crawford County (near Grayling) site. However, it can be readily identified by the leaves throughout the summer. The leaves have long petioles (leaf stems), are heart-shaped and a distinctive grayish color underneath. Any species that spreads via both rhizomes and seeds should be watched. Coltsfoot has only been collected in eight counties in Michigan but has spread rapidly east of us. Normally it does not compete with native species, preferring to grow where the soil has been disturbed, but it is now moving into native sites in Pennsylvania. This species should be reported whenever it is found (U.S. Forest Service Plant Database).

Coltsfoot initially was imported into this country for its supposed medicinal properties. The leaves were used to treat coughs and bronchial congestion, but possess a liver toxin. There is no current medical use.
Copyright 2013 by Donald Drife

Webpage Michigan Nature Guy
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