Missouri Orchids – (Platanthera flava var. herbiola) – Tubercled Orchid

Here is my last new orchid for the season. It is also probably the orchid I had to work the hardest to find in this entire project. Platanthera flava var. herbiola is classified as S2 (imperiled) in Missouri due to the very few remaining populations. This is an orchid that likes its feet wet and can be found in a variety of habitats containing moist to wet soils. After trying unsuccessfully in 2020, Pete and I went back to the same location this year – a wet prairie in southern Missouri in early June. This was very tough searching as the high temps, strong sun and saturated air created a potentially dangerous heat index. We tried our best, slowly slogging through the already quite thick prairie. Just when it looked like Pete was wanting to throw in the towel, we came across a patch of less-dense vegetation with water about ankle-high. Here we found young orchids that numbered in the hundreds. Unfortunately, most were on the early side and were not fully flowering but we did find a few that made us happy. We also found that many of the orchids in this group had grazed top leaves – most likely from white-tailed deer that usually find orchids to be very appetizing.

Platanthera flava var. herbiola, the 33rd Missouri orchid species I have been able to see and photograph.

There is another variety of this orchid, P. flava var. flava that is also found in Missouri. Recently Pete and I tried to find this in most of the known locations but came up short. As of now my quest stands at 33 of 36 orchid forms that can be found in the state (36 is my accepted number and others may disagree). In addition to P. flava var. flava, I also need to find Coeloglossum viride (Long-bract Frog Orchid) – this species is known from a single location in the state but apparently does not flower and Epipactis helleborine, the broad-leaved helleborine – the exotic orchid that is becoming naturalized in this state but originates in Asia and Europe. Finding these three remaining orchids should be quite the task and I look forward to attempting these next year.

The longer floral bracts, looser inflorescence and three leaves are among a few of the characteristics that identify this as Platanthera flava var. herbiola and not P. flava var. flava.

I have run into a couple other circumstances in our orchid flora where intermediate forms have caused problems in determining the identity of a plant or population. Where these two varieties overlap, as they seem to do in Missouri, there are intermediate forms between these two varieties as well. I will hope that when I do find a potential flava variety that this will not become a problem.

Platanthera flava var. herbiola is the more southern variety. Here another distinguishing characteristic can be observed – the lip of variety herbiola is longer than it is broad, whereas the lip of variety flava is as broad as it is long, being almost square or circular in appearance.

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!

Synchlora aerata (camouflaged looper)

Back in mid-June I discovered a number of Synchlora aerata (camouflaged looper, wavy-lined emerald moth) that were using our coreopsis as host. Not only are these spectacular adult moths in the family Geometridae, but they are obviously special while in the larval phase as well. These caterpillars are known for attaching bits and pieces of the plant tissues they feed on (often flower petals) to their backs as means of camouflaging against their predators.

The Synchlora aerata, on Coreopsis sp. in a suburban wildflower garden in St. Louis County, MO, USA
I often find these guys with their camouflage dull, dry and not very attractive. You can change this pretty easily by placing them in a container with a fresh native flower of your choice. Hopefully within a day or two the caterpillar will have adorned itself with a fresh and colorful coat!

From the Home Garden – Callirhoe bushii (Bush’s poppy mallow)

Photographed on June 11th of this year. I chose this species of Callirhoe because it is the most likely to stay small and behave in the front yard beds. However, I fear that the primarily clay soils will get the worst of it and it won’t stick around long. Of the three plants, only one made it to flower. These guys are adapted to more xeric and well-draining soils.

Leaf and flower of Callirhoe bushii (Malvaceae)

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.

The Last of the Ladies Tresses

This year I was able to find and photograph the last two of the Spiranthes (ladies tresses) orchids that can be expected to be found in Missouri.

First up is a plant that Casey and I found in Nevada County, Arkansas on May 9th. To my knowledge, S. praecox (grass-leaved ladies tresses) is found in only one location in the Show Me State. However, after checking for it on a few occasions, it looks as though the plant(s) did not bloom this year. Hopefully this population is still there and will bloom in a future year. The couple of blooming spikes Casey and I found in Arkansas were very striking, with deep green venation on the labellum.

Spiranthes praecox, grass-leaved ladies tresses

It is interesting to me that the final two Spiranthes orchids I had to add to my list are the largest two species by far. While S. praecox can reach heights of up to 75 cm, S. vernalis (spring ladies tresses) has been recorded at a meter in height! This species is distributed throughout the state, but is considered locally rare. This plant was found at Otter Slough C.A.

Spiranthes vernalis, spring ladies tresses

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.