Back to the Prairie Platanthera

We really lucked out this past June when Casey and I took a trip to the northwest of Missouri in search of the two state-endangered prairie-fringed orchids. We were not sure if we would find Platanthera leucophaea (eastern prairie-fringed orchid) at all and chances were iffy to find both species flowering simultaneously. During some years, there may be gaps in the phenology of flowering of these two species in the state, which would require at least a couple of these long trips. As mentioned above, we not only found both species in our search but found them both at near-peak bloom.

First up is Platanthera praeclara (western prairie-fringed orchid) that we found in a reliable spot in Harrison County.

The state-endangered and federally-threatened Platanthera praeclara was photographed with a backdrop of tallgrass prairie in Harrison County, MO
Naturally pollinated by nocturnal sphinx moths, some state programs are now hand-pollinating prairie-fringed orchids in efforts to increase populations and reintroduce the plants to new areas.

We were thrilled to find a population of approximately 40 Platanthera leucophaea (eastern prairie-fringed orchid) plants at a Grundy County location.

A pair of Platanthera leucophaea stand tall in a wet prairie in Grundy Co, MO.
The long nectar spurs require an insect with a long proboscis to act as pollinator of Platanthera leucophaea.
A pair of grasshopper nymphs feeding on Platanthera leucophaea. This was the only plant we observed with heavy arthropod feeding pressure like this.

Hottonia inflata (American Featherfoil)

Many thanks to Stephen, Pete and Casey for introducing me to this special plant this spring. Hottonia inflata, or American featherfoil, is ranked as imperiled (S2) in the state of Missouri and is a species of conservation concern in most states within its range. The destruction of wetlands habitats in the U.S. is the cause of the scarcity of this winter annual member of the primrose family (Primulaceae). The stems of this plant are spongy organs filled with air pockets and are the characteristic described in the specific name – inflata.

The gas-filled stems and leaves of Hottonia inflata allow this aquatic member of the primrose family to keep its flowers above the water’s surface.

The Beardtongues?

Here is a genus that I find interesting. The Penstemon is made up of approximately 270 species and is the largest genus of flowering plants that are endemic to North America. Now classified in the plantain family (Plantaginaceae), this is a very diverse genus found across a variety of habitats and altitudes. Most species should be readily identified as a Penstemon due to their unique flower morphology. The corolla is a fused tube, comprised of five petals that can be identified as lobes in a two on top, three on the bottom configuration. Inside the corolla you will find two pairs of stamens with anthers pushed towards the top of the open mouth. In between the fertile stamens is a staminode that lies towards the bottom of the tube. This sterile modified stamen usually ends in a brush-like structure. This is the eponymous “beardtongue”. The generic name, Penstemon, meaning “stamen-like”, also refers to this staminode.

I got to meet four species of Penstemon in bloom this year – two of which I planted in the garden. I was happy to see them bloom in their first season.

Penstemon pallidus (pale penstemon) from my front garden in St. Louis Co., MO.
A closeup of Penstemon pallidus flowers. Note the yellow beard (staminode) that is thought to aid in pollination by pushing hymenopteran pollinators towards the stigma and anthers located at the top of the corolla tube. Also note the dark nectar guides that point towards the back of the tube.
Penstemon digitalis (foxglove beardtongue) is the most common and least particular member of the genus in eastern Missouri. These plants were found in a field at Beckemeier Conservation Area in St. Louis County.
The flowers of Penstemon digitalis are mostly white in color and have a relatively long blooming period compared to other local members of the genus.
Penstemon tubaeflorus is a showy white penstemon that is found primarily in the southwestern quadrant in Missouri. These photos were taken at Tingler Prairie Natural Area near West Plains, MO.
Here you can see why this species gets its common name of ‘trumpet beardtongue.’
The large and showy flowers of Penstemon cobaea (prairie beardtongue). These were photographed from the author’s front garden in St. Louis Co., MO.
I used focus stacking to capture the details in the flower of this Penstemon cobaea (prairie beardtongue). Note the two pairs of stamens that wrap around the inside of the corolla and present their pollen-filled anthers at the top. The stiff brush-like beard of the staminode pushes would-be pollinators towards these reproductive organs.

-OZB

Those Lovely Spiderworts

Casey and I ran into a number of spiderworts in forests, glades and prairies across Arkansas and southern Missouri during our trip in May. Although Casey did his best in identifying the plants as we came across them, my field note taking can often leave a lot to be desired and I didn’t record which photo was which plant. With approximately ten species of Tradescantia in this geography plus a few known hybrid situations as well as multiple flower colors possible in some species, identifying these just by closeup photos of the flowers would be challenging even for the experienced botanist. So, I am satisfied just to focus on the forms, colors and insect interactions of these flowers as seen in these photos.

This has me thinking about the possibility of sending in my 5D mk iv into Canon to have the conversion that enables voice notes recording. I used this a couple times when I had the 1D mk iv and think it would be useful during these trips where we are hurrying from plant to plant and location to location and I realize I left my pen and notebook in the car or at home, or am simply to lazy too use them.

Helenium virginicum (Virginia Sneezeweed)

The Virginia Sneezeweed is a Missouri state endangered and federally threatened species of Helenium, first discovered outside of Virginia, by our own Julian Steyermark. I photographed these in August, 2020 at Tingler Prairie N.A. I encourage you to read this great article by Bridget Macdonald to read more of the story of this plant.

Through extensive searching and reintroduction efforts, there are now more than 60 known populations of Helenium virginicum (Virginia Sneezeweed) found in Missouri.

Astranthium ciliatum (Western Daisy)

This fantastic little one is the western daisy (Astranthium ciliatum) that we found at Middle Fork Barrens Natural Area. In the xeric, shallow soils of the barrens this daisy was single-stemmed and and no more than 6″ off the ground. If only they would behave like this in the home garden! Their range is centered in Oklahoma and Arkansas although they can be found in southwestern Missouri. These were beautiful little plants and rank up with my favorites in the family.

Astranthium ciliatum, or western daisy, is a spring-blooming member of the Asteraceae.

Missouri Orchids – Liparis liliifolia – Large Twayblade

Today’s orchid, Liparis liliifolia, (large twayblade, purple twayblade, lily-leaved twayblade, mauve sleekwort) is considered one of the most abundant in Missouri with quite a large range across the state. They have the potential to be found almost anywhere in the state with moist to dry-mesic forests, but do need open spots with partial sun. This is a species that benefits from disturbances and clearings due to fire, tree falls and human activity like trails where they are most likely to be found.

Liparis liliifolia with its pair of fleshy basal leaves and flowering raceme that blooms from the bottom to the top.

Insects are the most obvious choice for pollinators, however, there have not been many recorded observations of specific efficacious visitors and more information is needed to determine what species are responsible for pollinating this species. There is no real fragrance associated with these flowers. The purplish translucent flowers have been hypothesized to attract flesh flies which might be efficient pollinators. The primary mode of reproduction seems to be vegetative via underground corms.

This male mosquito was observed feeding at the nectary of this Liparis liliifolia flower. However, he was too small to come into contact with the column and is not considered an efficacious pollinator.

The flowers are set in the typical 3-petals and 3-sepals configuration of the family. In this case, the lower petal, or “lip”, is mauve in color and translucent. The translucency was enhanced when the lip was wet. The two lateral petals are filiform, or worm-like. To me they resembled the nectar spurs found on some orchids, but these are not hollow and do not contain nectar. The three sepals are blade-like, with one facing straight upwards behind the column and two are lateral and underneath the lip. It would not be a stretch to say the entire flower might mimic some insect.

A young developing flower stalk of Liparis liliifolia next to flowering stalks and seed capsules of last year’s efforts.

The large twayblade is definitely an interesting Missouri orchid. I will look for these close to home in the coming years and perhaps get some photos of their pollinators visiting.

-OZB