Monthly Archives: June 2015

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

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Maple Spinners

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Maple Seeds

Maple Seeds Photo by Robert Muller

Recently a friend remarked, “There are not many spinners this year.” I was puzzled until I realized my friend was talking about maple seeds. When I was a kid we called them propellers or helicopters. I took an informal Facebook poll asking what people called them and they added “Whirligigs” or “Whirligiggers” and appropriately “pain in the butt”.  Technically, it is a samara that is defined as “a winged fruit that does not split open.” Elms, Maples, and Ashes have samaras.

Michigan has six native species of Maples (seven if you recognize Black Maple as distinct from Sugar Maple). The non-native Norway Maple (Acer platanoides) is a too common escaped species.

Silver Maple

Silver Maple

Silver Maples (A.sarrharinum) and Red Maples (A. rubrum) have the best spinners. Silver Maple samaras are 3-6cm (1 ¼ to 2 ½ inch) long and the pair forms a widely diverging angle although often only one seed fully develops.

Red Maple

Red Maple

Red Maple samaras are smaller 1-2.5cm (1/2 to 1 inch) long and the pair is more V-shaped. Often they are reddish. Sugar Maple (A. saccharum) pairs are U-shaped with the samara almost parallel to each other.

Boxelder

Boxelder L- dried seeds in winter R-fresh seeds

Boxelder (A. negundo) has V-shaped pairs and will sometimes hang on the tree all winter. Norway Maples have samara pairs widely spaced so the pairs are almost straight across.

Striped Maple

Striped Maple or Moosewood

Mountain Maple (A. spicatum) and Striped Maple also called Moosewood (A. pensylvanicum) have seeds in branched clusters called racemes. Mountain Maple has seeds approximately 1cm (3/8 inch) long. In Striped Maple the seeds are 2cm (3/4 inch) long. I seldom need to identify maples solely from their seeds. All of these species have other useful characteristics to help determine their identity.

Thanks to Robert Muller for the use of his photo showing the seed of the four species.
Copyright 2015 by Donald Drife

Webpage Michigan Nature Guy
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