The genus Silphium

The Tucker mini-prairie, located just to the south of the Tucker greenhouse is home to lots of members of the Asteraceae family.  This family, also known as the sunflower or daisy family is one of the largest plant families on the planet, next to the Orchid family.

Right now there are lots of yellow flowers blooming in the mini-prairie and lots of these belong to the sunflower family.  Some members of the Asteraceae family that are blooming right now are Ashy sunflowers, or Helianthus mollis, Gray-headed coneflowers, or Ratibida pinnata and two members of the genus, Silphium.  We also have Mullein, or Verbascum thapsus found in the Scrophulariaceae family.

In this post though, I plan to briefly discuss the two members of the genus Silphium.  They are the Compass plant, or Silphium laciniatum and the Cup plant, or Silphium perfoliatum.

The Compass plant is so named because their very oddly-shaped leaves actually orient themselves with the flat portion of their leaf blades facing east-west.  Check out


The Cup plant is so named because its odd leaves attached to the stem opposite from each other and form a cup that can hold rain water.


Read more about the Cup plant here

Dr. David Dunn…Because of him, we have the Tucker Greenhouse.

Dr. Dunn taught Plant Taxonomy for years at MU.  He was largely responsible for the design of the Tucker greenhouse.  He collected the majority of the plants now growing in the greenhouse too.  I recently visited with his daughter who shared stories with me of her dad, ‘Doc’, and of plant collecting trips she went on with him and his graduate students all over Mexico & Central America.  This photo of him was taken on one of those many trips.

Dr. David Dunn

My coworker Melody Kroll and I recently went to MU Archives to look at the huge collection housed there of Dr. Dunn’s research, etc.  In a file labeled ‘Plant Collection trips ’69-’71’, I found his hand-drawn phylogenetic trees of various plant families. See two of the best below.

Also, we discovered lots and lots of letters people had sent to him asking for his help in identifying plants.  He was quite well known for his plant identification skills.  He would take the time to ID all the plants people sent to him, and he’d write back a very personal, detailed reply about each plant. There were hundreds of these.  One really stuck out for me.

A woman in New York submitted some leaves to Ralston Purina (the pet food corporation) asking them to ID a plant that her dog kept eating.  She thought that since it didn’t make her dog sick, maybe they should use this plant in their pet food recipe. Ralston Purina sent her letter to Dr. Dunn, and sent the woman a letter telling her that they’d submitted her leaf sample and her letter to a renowned Botanist at the University of MO who was the expert in identifying plants.

Dr. Dunn’s daughter also shared with me that her dad was a frequent guest of a local television show called ‘Of Interest to Women’.  This was a gardening show about spring planting, preparing gardens for planting in fall, and how and when to plant a certain plant.

More to come on Dr. Dunn and his amazing career at MU.