The Monthly Orchid: the Frog

See any frogs? (MWI)

Welcome back to The Monthly Orchid, a series about native orchids of South Dakota. This episode features Dactylorhiza viridis, the Frog Orchid, one of the most widespread orchids in the world. It occurs across Eurasia and Canada, and in the United States from Alaska to North Carolina. But it's new to me. Here's a chance to get to know it before I search for it in the wild.

In South Dakota, the Frog Orchid appears to be limited to the Black Hills and Harding County (northwest corner of the state). But not all that far away, in central Minnesota, it is said to be widespread and “most prevalent in upland hardwood forest along the tension zone between the western prairie and eastern forest”. This is yet another species that makes me wonder: With more thorough botanizing, will it be discovered in hardwood forests in far eastern South Dakota?

Frog Orchid in Minnesota (MWI).

In South Dakota, Dactylorhiza viridis has been found mainly in forested areas, occasionally in mountain meadows. Go Orchids reports that in North America “it prefers moist habitats, growing in wet coniferous forests, tundras, prairies, meadows, and bogs.” So I was surprised to read that in the UK and Europe, it’s commonly found in grasslands.

Frog Orchid in grassland; Beddingham Hill, England (Keith DP Wilson).

In his 1938 Wildflowers in Britain, the honorable R. Gathorne-Hardy wrote of the “squat green-flowered frog orchid”, which he considered “grotesque” (Fay et al. 2015). Gathorne-Hardy may have been a highly respected botanist, but I have to disagree. While it’s true that the Frog Orchid is a bit on the stout side, “squat” is inappropriate. Perhaps he knew it only from grasslands in the UK (photo above). On more favorable sites, plants can be tall and graceful.

A Frog Orchid amid greenery on a hospitable site in Finland (Kari Pihlaviita).

Dactylorhiza viridis, also known as Coeloglosum viride (1), used to be included in the genus Platanthera, of which we have six species in South Dakota. These are our bog or rein orchids. Not surprisingly, they are similar to the Frog Orchid—slender green plants with inconspicuous green to white flowers, and flowers with a spurred lip petal (labellum). Even so, the Frog Orchid usually can be easily distinguished by several features, especially in combination—leaves, inflorescences, lip petals and tubers.

Leaves are alternate on stems (vs. all basal in some Platanthera species).

Frog Orchid leaves clasp the stem or nearly so (MWI).

Inflorescences often (but not always) have long leaflike bracts subtending the flowers, hence “Long-bracted Orchid”—another of its common names.

Dactylorhiza viridis in Cumbria, England; note prominent bracts in inflorescence (naturalhistoryman).

The lip or labellum (lowermost of an orchid flower’s six petals) has a small saccate (bladder-like) spur at the base, and is 3-lobed at the tip. The middle lobe is much smaller than outer ones and sometimes said to be tooth-like.

Dactylorhiza viridis; upper arrows point to globular spurs, lower to 3-lobed tips of lip petals (note tiny central lobe at arrow tip). Photo ©Al Schneider, http://www.swcoloradowildflowers.com.

One more distinguishing feature—Frog Orchids have palmate tubers as the next image shows. But I am NOT recommending you dig up a plant to check! Tubers are mentioned mainly to explain the genus name: Dactylorhiza (Latin) means “finger root”. Finger number ranges from 2 to 5.

Platanthera viridis; Berlin, R. Friedländer & sohn, 1904. Biodiversity Heritage Library.

But wait! Surely the most reliable feature for confident id is the eponymous frog …

MWI (labels mine).

... wrong!!!

Much searching and consultation revealed that whether the Frog Orchid looks anything like a frog is a matter of debate. Some orchid enthusiasts see suggestions of frogs in the flowers. For example, the Wild Flower Finder sees a frog’s head in the hood formed by the upper tepals—“think Kermit the Frog.” Add the two longer lobes at the tip of the lip petal, and maybe it's a leaping frog!

However, others find nothing frog-like about the Frog Orchid. In The Wild Orchids of Britain (1950), Jocelyn Brooke is emphatic on this point:

“one must enlist the eye of faith to detect any batrachian quality in this orchid. Apart from the fact that it is small and green, there seems to the ordinary observer nothing frog-like about it. …. To say the least, the name is of no assistance as a means of identification.”

To be honest, I DO see leaping frogs, for example in the photo below. And you? See any frogs? Feel free to explain in Comments.

Frog Orchid in Sussex, England; reddish to maroon tepals are fairly common (Keith DP Wilson).

Note

(1) Frog Orchid has a long history of synonymy, listed here chronologically (from Fay et al. 2015). Linnaeus was the first to assign a binomial—Satyrium viride in 1753 (any ideas as to why he chose "Satyr"?). This was followed by Orchis viridis, 1769; Habenaria viridis, 1813; Gymnadenia viridis, 1817; Sieberia viridis, 1817; Coeloglossum viride, 1820; Entaticus viridis, 1821; Chamorchis viridis, 1827); Platanthera viridis, 1829; Himantoglossum viride, 1830; Peristylus viridis, 1835; and finally, Dactylorhiza viridis, 1997.

Dactylorhiza viridis and Coeloglossum viride are both used currently; Platanthera viridis persists in older sources.

Sources

Brooke, J. & Bone, G. (1950). The Wild Orchids of Britain. Bodley Head, London.

Fay, M.F., Sayers, B. & Taylor, I. 2015. 802. Dactylorhiza viridis. Curtis's Botanical Magazine, 32: 33-41.

Flora of North America. Coeloglossum viride. Accessed October 2026.

Go Orchids. Dactylorhiza viridis. Accessed October 2026.

Southwest Colorado Wildflowers. Dactylorhiza viridis. Accessed October 2026.

Minnesota Wildflower Information. Coeloglossum viride. Accessed October 2026.