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

“What are all of those those yellow flowers?”

yellow flowers

Helianthus mollis or Ashy sunflower is found in the Asteraceae family.  These dense heads are loaded with pollinators right now.

Helianthus mollis, commonly called Ashy or Downy sunflower is a predominant species in the Tucker Mini-Prairie, and it has been blooming for weeks now.  This plant belongs in the Asteraceae or Daisy family, one of the largest plant families on earth.  The root system of this plant is rhizomatous, allowing it to spread uncontrollably underground.  It can spread very aggressively, and its root system exudes allelopathic chemicals that can inhibit the growth of other plants surrounding it. Common habitats for this plant are dry to mesic prairies, sand prairies, rocky glades, & roadsides.  This plant would take over this tiny patch of ground called the Tucker Mini-Prairie if we didn’t constantly cut it back and remove seed heads.

Lots of different types of pollinators visit the flowers of the Ashy sunflower. Primarily bees visit the flowers for nectar or pollen.  Goldfinches are partial to the seeds of this plant.  Two caterpillars of the butterflies Chlosyne nycteis (Silvery Checkerspot) and Chlosyne gorgone (Gorgone Checkerspot) feed on its leaves.

Compass Plant

Compass Plant head inflorescence

Compass Plant head inflorescence

Silphium laciniatum, commonly called Compass Plant is a native Missouri plant found in the Asteraceae family.  Compass Plants can reach heights of 3 meters or more.  They have a head inflorescence, typical of members of the Asteraceae family.  Several heads are alternately arranged along the thick, hairy stem.  The leaves of the Compass Plant are most unusual as they are aligned vertically on the stem.  The name ‘Compass Plant’ comes from the fact that the basal leaves on the plant tend to align their edges or margins north and south.


Like other members in the Silphium genus, the ray flowers on the head, or capitulum inflorescence are yellow with darker yellow disk flowers in the center of the head. Many different kinds of pollinators visit the Compass Plant throughout the growing season.

“Long-tongued bees are the primary pollinators of the flowers, including bumblebees, Miner bees, large Leaf-Cutting bees, and others. Short-tongued Halictine bees and Syrphid flies also visit the flowers, but they are less effective at pollination. Occasionally, Sulfur butterflies and Monarchs may visit the flowers for nectar. Several species of insects are specialist feeders of Compass Plant. This includes the uncommon Okanagana balli (Prairie Cicada), whose grubs feed on the large taproot, while a Rynchites sp. (Silphium Beetle) and its larvae feed on the flower heads and stems. The larvae of Antistrophus rufus and Antistrophus minor (Gall Wasp spp.) feed within the stems, forming galls that are not visible from the outside. Nonetheless, they attract the hyperparasitic wasp Eurytoma lutea, whose larvae feed on these gall formers. Similarly, the larvae of Mordellistena aethiops (Tumbling Flower Beetle sp.) feed within the stems, while the adults may eat the flowers. The oligolectic aphid Iowana frisoni sucks the juices from the flowering stems.” –

June 16th blooms in Tucker Hall flower beds

yellow flower

Coreopsis tinctoria, commonly called Plains coreopsis, is found in the Asteraceae family.

white flower

Cephalanthus occidentalis, or Buttonbush, is found in the Rubiaceae family. This small tree happens to be the Missouri State Champion tree.  It is located on the south side of the Tucker Greenhouse.

yellow flower

Silphium perfoliatum, or Cup plant, is found in the Asteraceae family.

red and yellow flower

Ratibida columnifera, or Mexican hat, is found in the Asteraceae family.

orange flower

Bee on Asclepius tuberosa, commonly called milkweed, found in the Apocynaceae family.

yellow flower

Opuntia humifusa, or Prickly pear, is found in the Cactaceae family.

pink flower

Saponaria officinalis, or Soapwort, is found in the Caryophyllaceae family

Milkweed beetles

Monarch butterflies aren’t the only insects interested in milkweed plants.  Just today I spied a red milkweed beetle (Tetraopes tetrophthalmus) on a Asclepias syriaca plant right outside of the Tucker Greenhouse.  The scientific name for this beetle is Latin for ‘four eyes’.  This beetle looks as though it has four eyes since each antenna bisects its eyes.  They are also called milkweed longhorns because of their long antennae.

When I first saw this beetle, it was sort of hiding down in the whorl of the leaves, but it had clearly been chewing the leaves.  It turns out that milkweed plants in the genus Asclepias are the host plants for this beetle.  Milkweed plants contain certain toxic alkaloids, so it has been surmised that the beetle gets a certain amount of protection from predators by ingesting these toxins.  If you’d like to learn more about these cool insects, click here.

Check out these very colorful Milkweed beetles below.

Milkweed beetle on Asclepius syriaca leaf

Milkweed beetle on an  Asclepius syriaca leaf


Asclepius tuberosa, Butterfly weed has just begun to bloom……..

orange flower

Asclepias tuberosa, commonly called Butterfly weed, is found in the Apocynaceae, or Milkweed  family.  Butterfly weed is a native Missouri, drought tolerant plant with orangish yellow flowers. These beautiful flowers usually start blooming in June and continue through August.  The Tucker Rock Garden milkweeds have just now begun to bloom. These flowers are a nectar source for many different butterfly species, honeybees, digger bees, leaf-cutting bees, Halictid bees, thread-waisted wasps, Sphecid wasps, and even Hummingbirds.

The leaves are a very important food source for Monarch butterfly larvae.  To read more about the very cool Monarch butterfly/Milkweed relationship, click here.


If you look closely at the top left in the photo above, you’ll see two lady bugs mating.  I looked a little more closely and saw that this particular milkweed plant had several milkweed or oleander aphids on the stems.  Ladybugs love to eat aphids and are often used as beneficial insects to feed on plant pests like aphids in greenhouses, so it’s no wonder these ladybugs congregated on this plant.  To read more about oleander aphids, click here.

The genus ‘Asclepias’ comes from the Greek god Asklepios, the god of medicine.  Asclepias tuberosa is also called pleurisy root and was once considered to be a cure for pleurisy (inflammation of the lungs).  Species names are often adjectives that somehow describe a given plant.  In the case of Asclepias tuberosa, ‘tuberosa’ refers to the tuberous root system of the plant.

The seed pods of Butterfly weed are called follicles.  Botanically speaking, a follicle is a dry, dehiscent fruit composed of a single carpel and opening along a single side. The seeds themselves are packed tightly inside the follicle.  Later on in the fall when the follicle dries and opens (dehisces), seeds emerge with an attached tuft of silky hairs that aid in seed dispersal when blown in the wind.  The pictures below show the dried milkweed follicle packed with seeds equipped with these soft, silky hairs.




Tucker mini-prairie & more rock garden blooms


Callirhoe involucrata, commonly called Purple Poppy Mallow, is found in the Malvaceae family.  They prefer dry soil, full sun, and readily reseed themselves.


Tradescantia ohiensis, commonly called Ohio Spiderwort, is found in the Commelinaceae family.  Spiderworts have beautiful bluish-purple flowers with three petals, bright yellow anthers, and very hairy purple filaments.  They bloom from late spring to mid-summer and prefer to grow in full sun, and they can also grow in very dry soil.  Long-tongued bees, especially bumblebees are common pollinators.


Ratibida pinnata, commonly called Gary-headed Coneflower, is found in the Asteraceae family.  These beautiful, yellow coneflowers prefer full sun and dry conditions.


Ratibida columnifera, commonly called Mexican Hat, is found in the Asteraceae family.  The common name, ‘Mexican Hat’, refers to the resemblance the head inflorescence has to a sombrero.  This native Missouri plant prefers full sun, and can withstand very dry soil.  It reseeds readily.


Primrose-Oenothera sp., Onagraceae family

Tucker Rock Garden coneflowers

Echinacea purpurea, or Purple Prairie Coneflower is found in the Asteraceae family.  Coneflowers typically bloom from late May through August, and they thrive in full sun to part shade.  They tolerate drought and heat very well.  The genus name of Echinacea comes from the Greek word echinos meaning hedgehog, referring to the appearance of the prickly central cone, or seed head. The flowers are visited by many different pollinators such as long-tongued bees, Halictid bees, bee flies, butterflies, and skippers.  Small songbirds such as Goldfinches often eat the seed heads of these flowers.

Echinacea is a medicinal plant as well. Native Americans used it to treat infections and wounds, but today people use it as a way to boost their immune systems.  It’s used to fight the common cold and reduce symptoms of sore throat, and fever. The Tucker Rock Garden has several Purple Coneflower plants. The photo below is of a very young flower.  When the flowers are fully mature, each dense head inflorescence will be filled with numerous pinkish purple ray flowers and in the center of the head there will be hundreds of reddish orange disk flowers.  So, the next time you look at a sunflower, coneflower or daisy, you are actually looking at two different types of flowers condensed into one head inflorescence botanically known as a capitulum.

I’ll be posting more photos of these cone flowers as they mature……..

Young coneflower head

Young coneflower head in late May 2016

Same cornflower one week later


Same coneflower one week later