Orchids: A View of Our Tropical Missouri

Hiking trips in Missouri lead outdoor enthusiasts to a wealth of discovery. Spring peepers and songbirds voice in a new year of adventure, box turtles take life easy as they bask in the warmth of the summer sun and wildflowers paint our woodlands, meadows and stream sides with their vibrant color. Among that myriad of wildflowers are a group of breathtaking plants some may consider out of place when it comes to the hills, hollows and rocky outcrops of the Show-Me State. Their family name sounds as tropical as mango or papaya, yet Missouri harbors more than 30 species of orchids.

Missouri’s orchids belong to a large flowering family, Orchidaceae, comprised of approximately 15,000 species worldwide. Their striking flower characteristics, growth style and habitat requirements make them a unique group of plants. Spiraling and twisting as they emerge from the ground, many orchids perform a somersault during development, with their flowers eventually hanging nearly upside down to create a look all their own.

Hidden Jewels

Depending upon the species, observing orchids in Missouri is often by chance, as many do not make flowering appearances each year. Populations thought to have vanished may reappear several years later, while other groups bloom consecutively for years. Without their showy blossoms and with only a few leaves above ground, most of our larger orchids go unnoticed. Due to either their earthy tones or their association with larger plants, small-flowered species, such as the cranefly orchid, Tipularia discolor, green adder’s mouth, Malaxis unifolia, and Adam-and-Eve orchid, Aplectrum hyemale, are hard to spot even when sporting their full floral arrangements.

Many of Missouri’s orchids bear feminine names, notably the ladies’ slippers and ladies’ tresses. Had Cinderella been handed a floral slipper to try on instead of a glass one, she may have been exalted to a higher level than princess, for the slipper orchid genus, Cypripedium, refers to the lovely footwear of the Greek Goddess Aphrodite.

Lady’s Slipper

Nestled within the rich humus soils of Missouri’s woodlands, valleys and fens are three species of lady’s slipper orchids that showcase their dainty, ballerina-style blossoms from April into early June. With their striking colors, each species is easily distinguished from the others. The stem of the showy lady’s slipper, Cypripedium reginae, may grow more than 3 feet tall and have between six to 10 large oval leaves. The large, inflated flowers are white to slightly off-white with a purple or purplish-pink blush. Yellow lady’s slipper, Cypripedium calceolus, also displays an inflated lip along with three yellowish-brown sepals. The two lateral sepals spiral like locks of curly hair on each side, while the broad-shaped top sepal arches over the bright, canary-colored lip. Although found bordering streams and ravines in both northern and southern Missouri, this species appears to be more abundant in the Ozark region of our state. A smaller variety of the yellow lady’s slipper is found more commonly in western Missouri and has more richly colored brown, lateral, twisted sepals. Princess-like with their porcelain sheen, small white lady’s slipper orchids, Cypripedium candidum, are seldom encountered throughout the state and are under serious threat due to over-collection and disturbance of key habitat sites.

Grass Pinks

Many orchids depend upon insects for pollination, and their unique flower structures help to ensure pollination success. In the case of the two Missouri species of grass pink orchids, bees play a vital role. Perceiving the flower’s bearded column as anthers, a bee lands to collect pollen and causes the flower’s lip to tip downward. The bee struggles to free itself, and the orchid is successfully pollinated.

Grass pink orchids occur in habitats south of the Missouri River. Calopogon oklahomensis, prairie grass pink, is found primarily on upland prairies in southwestern Missouri. Visitors to Diamond Grove Prairie Conservation Area in Jasper County in May sometimes encounter this beautiful fuchsia-colored plant. Though it doesn’t bloom every year, it is worth looking for.

Swamp grass pink, Calopogon tuberosus, is restricted to wet meadows and Ozark fens of the southeastern part of the state. With a showier appearance than prairie grass pink, its pink blossoms may be rose-pink, white or brilliant magenta.

Twayblades

Twayblade orchids enjoy our Ozark fens and damp woodlands during the cooler spring months of May and June. First discovered in Shannon County by botanist Julian Steyermark, Loesel’s twayblade, Liparis loeselii, is currently a Missouri species of concern. Its Missouri range is limited to just a few southeastern and central Ozark counties, notably Butler, Carter, Madison, Wayne, Shannon and Laclede. Its cousin, the lily twayblade, Liparis liliifolia, is more common and may be observed in wet meadows and moist rocky woodlands in both the Ozarks region and northern portion of the state. A third twayblade species, Listera australis, southern twayblade orchid, was discovered growing in Missouri in April 2009 by members of the Missouri Native Plant Society.

Fringed

Upon our native prairies, alongside sinkhole ponds and within select mesic forests, grow a regal group of North American plants, the rein orchis, or fringed orchids. Fringed orchids found in the United States are members of the genus Platanthera and have more than 500 tropical relatives worldwide. Eight species are known to have occurred historically in Missouri and most are in a perilous state, mainly due to habitat changes.

With local names such as soldier’s plume, frogspike, ragged orchid, prairie fringed orchid and pride-of-the peak, it is clear that this assemblage of orchids is not your average daisy or run-of-the-mill rose. And while each species is unique, they share a few common characteristics. Arising from tuberous roots, the smooth stem usually supports two to eight leaves and is topped with a spike covered with several fragrant and sometimes brightly colored individual flowers. The lower lip may be entire or fringed and has a long spur-like appendage that extends downward. For all of these orchids, summer is their time to shine, with June, July, August and September being the best months to look for them in their preferred habitats.

Two of our native species, Platanthera praeclara, the western prairie fringed orchid, and Platanthera leucophaea, the eastern prairie fringed orchid, are currently listed as threatened under the U.S. Endangered Species Act. Due to invasive vegetation and land development activities these species have been pushed out of their native range, and sightings in Missouri are extremely rare. Interestingly, both western and eastern prairie fringed orchids are pollinated at night by sphinx moths, and thus depend upon these nocturnal insects for their survival.

Pogonia

Rarely encountered, Missouri’s pogonia orchids enjoy the seclusion of rich Ozark woodlands, fens and stream valleys. Remaining underground for several years without flowering, large and small whorled pogonias, Isotria verticillata, and Isotria medeoloides, have yellowish-green flowers and are observed far less frequently than the fragile white nodding pogonia, Triphora trianthophora. In fact, the small whorled pogonia is so rare that it has been documented only once in Missouri during the late 1800s from a single location in Bollinger County. The rose pogonia, Pogonia ophioglossoides, has only been viewed in Shannon and Reynolds counties.

Spiranthes

As summer gives way to autumn, many wildflowers fade and wither, but for a complex group of small orchids, the late summer into fall transition is a time to shine. Six out of the seven species of Spiranthes, also known as ladies’ tresses or pearl twist orchids, find their seasonal niche amongst the towering yellow blades of prairie and glade grasses and browning coneflower seed heads, as well as within low-lying wet meadow swales and Ozark fens. Although their preferred habitats may be readily distinguishable, the flowers themselves are hard to identify without use of a hand lens and your nose.

While August through early November signals the peak blooming period for nearly all Missouri Spiranthes, yellow-lipped ladies’ tresses orchid, Spiranthes lucida, may be found around bluffs and wet fields within the Ozarks during spring. Like other pearl twist species, this small flower showcases a spike of small, white, tubular-shaped flowers. When one of its individual flowers is viewed up close, however, a bright yellowish-orange spot can be seen on its square-shaped lip.

The autumn-blooming ladies’ tresses require a more scientific approach for identification, based primarily upon leaf shape, distinctive odor, or lack there of, and the twist of their floral structure. All seven species appear to be found more within counties south of the Missouri River.

Coral Roots

Arriving with autumn’s chilly temperatures and falling leaves are late coral roots, Corallorhiza odontorhiza, which, along with their spring-blooming relative spring coral root, Corallorhiza wisteriana, may be found in both southern and northern Missouri. Coral root orchids are colonial in nature and frequently consist of 10 or more plants per colony. Both early and late coral roots, as well as the crested coral root, Hexalectris spicata, are saprophytic and lack chlorophyll. Therefore, they rely entirely upon mycorrhizal fungi for all of their nutrients.

Worldwide many orchids are threatened, and Missouri species are no exception. The Missouri Species and Communities of Conservation Concern checklist lists nearly half of the state’s species as critically imperiled or, in some cases, extirpated.

Habitat disturbance, invasive vegetation competition and illegal digging and over-collection place many plant populations in jeopardy. Orchids collected in the wild have a poor chance of survival. Protection of habitat and leaving existing populations intact provide the best overall chance of these unique plants remaining a part of our native flora and for future generations to view the tropical side of Missouri.