Thalia dealbata (Powdery Thalia)

Thalia dealbata, or powdery thalia, is a fascinating plant that I was introduced to this past August while on a botany trip with Pete Kozich and Stephen Dilks. A member of the mostly tropical arrowroot family (Marantaceae), T. dealbata is the only member of this family to be found in Missouri and only in the low and wet areas of the southeastern portion of the state. We found these plants a little late in their flowering season but with a few blooms in prime condition remaining at Otter Slough Conservation Area.

A closeup look at the mirrored pair of flowers of Thalia dealbata (powdery thalia).

The leaves of Thalia are what the plants are primarily known for, looking very reminiscent of the cannas and very tropical in appearance. However, doing a little research after seeing these guys for the first time, I have become fascinated with the flowers and the pollination mechanism they developed. First of all, what appears to be a single flower in the image posted here is actually a pair of blooms in mirror image of each other. Additionally, the gorgeous purple petals are not petals at all but highly modified and sterile stamens (staminodes). This is just the beginning of the weird story of these flowers. These staminodes are key to a pollination strategy that literally throws pollen in the face of and often ends in the demise of all but the strongest of would-be insect pollinators. I was going to attempt to try and describe the pollination biology of this system, but this has been expertly described by Price and Rogers in a 1987 article published in Missouriensis. I highly recommend you give this a read!

Pete standing behind a nice batch of Thalia dealbata.

Agalinis fasciculata (Fasciculate False Foxglove)

Agalinis fasciculata, known as the fasciculate false foxglove and beach false foxglove was one of the more fascinating and unexpected plants I became acquainted with this year. A member of the Orobanchaceae family, this species is an annual hemiparasitic plant that does well in poor and sandy soils. I photographed these plants at the Missouri Mines State Historic Site in St. Francois County.

The genus Agalinis comes from the Greek – agan, meaning ‘very’ and linon, refering to ‘flax’, apparently in reference to the similarity of the flowers to those of flax. The species and common names refer to the fasciculate, or bundled manner in which the leaves are attached to the stem – something I failed to take any photos of this year. In my defense, much of the stem and leaves of these plants in mid-September were beginning to senesce and were not very photogenic.

Agalinis fasciculata (Fasciculate False Foxglove) in glorious bloom at Missouri Mines State Historic Site.
Many species of bees and flies like this syrphid fly act as pollinators of Agalinis fasciculata.
A rare six-lobed corolla of Agalinis fasciculata. This was the only six-lobed flower I found among hundreds I observed on this visit.

Eryngium prostratum (creeping eryngo)

Eryngium prostratum is an odd little member of the Apiaceae family that is found in the southeastern most part of Missouri. Along with it’s blue flowering heads, its closet living relative in Missouri is the relatively gigantic E. yuccifolium. These plants were photographed at Charleston Baptist Association Prairie in Scott County, MO on June 27, 2021.

Eryngium prostratum, or creeping eryngo, is a prostrate plant that roots at nodes as it creeps. It stays quite close to the ground and can be difficult to find.
Eryngium prostratum – not your typical carrot!

Styrax americanus (American Snowbell)

Found in approximately nine counties in southeastern Missouri, Styrax americanus can be found in low-lying wet habitats. This individual was found at Mingo National Wildlife Refuge. This plant is one of many different hosts of the promethea silkmoth (Callosamia promethea).

Styrax americanus – the American Snowbell. Photographed on May 22, 2021 at Mingo NWR near Puxico, MO.

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.