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| The pouch-like lips of Fairy Slippers (Calypso bulbosa) are exquisite with their purple patterns and bright yellow hairs. No wonder fairies collect them at night to wear for dancing! (NPS) |
Once again, I'm starting a series of posts about South Dakota plants—in part so that I can learn more about the state's flora (I'm still contributing to the online guide). In 2024 I wrote about trees, mostly the less familiar ones from the eastern part of the state. Last year I focused on ferns and fern relatives (lycophytes), and became a pteridomaniac in the process!
This year, after writing descriptions for sedges and rushes, and while starting on grasses, I considered doing a series about graminoids. But after a few weeks of struggling with species differentiated by tiny green structures, I came to my senses and went in a totally different direction—orchids! Their flowers are colorful, sweet-scented, diverse, relatively large, and highly-evolved.
Twenty-seven native orchid species have been reported from South Dakota. Some have large colorful flowers. Others have sweet-scented flowers, or flowers with unusual parts (e.g. threadlike or deeply dissected petals). But most of our species have flowers that aren't showy. They're small and subdued in color—white, greenish, yellowish, or brownish red. But up close they're gorgeous and obviously orchids.
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| Spotted Coralroot (Corallorhiza maculata); the white lip with purple spots has yellow gobs of pollen hanging over it; lip c. 6 mm long (MWI). |
Like almost all orchids (99%), ours have a
combination of features unique to the family: a LIP petal (tepal), a COLUMN consisting of the stamen(s) and pistil, POLLINIA made of pollen grains, and minute SEEDS.
The LIP or labellum is one of an orchid flower's six tepals (three sepals and three petals). Five of the tepals are more or less alike, but the lip is quite different—in shape, color, size and more. It's also distinctive among species, and is used in identification (fortunately it's easy to see). The lip appears to provide a landing platform for visitors, and species-specific forms are thought to be designed for specific pollinators—the product of coevolution.
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| Stream Orchid (Epipactis gigantea) has lips with "tongues"; these move when the flower is bumped, hence its other name: "Chatterbox"; flowers to c. 5 cm wide (Dcrjsr). |
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| The lip of Loesel's Twayblade (Liparis loeselii) is showy relative to the other tepals, 2 of which are horizontal and threadlike; flowers to c. 1 cm long (MWI). |
Most orchids have a single stamen, which is joined with the pistil to form a COLUMN. Among species, columns differ in size, shape, color and function. In White Lady's-slipper (below), the top of the column presses against the lip, preventing pollinators from leaving the way they came in. Instead they must exit via a narrow slit in the back of the pouch. Inexperienced bees may take up to 15 minutes to find the exit, and may fall prey to crab spiders lurking within! (
source)
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| Small White Lady's-slipper (Cypripedium candidum) has a glossy white inflated lip to 2.5 cm long; yellow flap with red spots is the column tip (MWI). |
In most orchids pollen grains are amassed into POLLINIA, bound together by threads of clear sticky viscin. Pollinia are carried off by pollinators to be deposited (hopefully) on stigmas of the same species. The advantages of dispersing pollinia rather than pollen grains will be explained shortly (below).
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| Ophrys orchid with a pollinator about to get hit with yellow pollinia (ErwinMeier; arrow added). |
Finally, orchids produce the tiniest of SEEDS, which number in the thousands or even millions per flower! This means that there are equally numerous ovules in a single pistil. Now we see the advantage of pollinia. Thousands or sometimes millions of pollen grains packed into a pollinium land on a stigma all at once, ready to fertilize the multitude of waiting ovules.
Orchid seeds are very different in another way. Most flowering plants (angiosperms) have double fertilization, producing seeds with both an embryo and a stash of endosperm to feed the seedling as it starts its life. But not orchids. There is no double fertilization, and the tiny seed contains no endosperm to sustain the baby seedling. Even the embryo is much reduced—just a small mass of mostly undifferentiated cells.
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| Seed of Autumn Coralroot (Corallorhiza odontorhiza), 0.2 mm long! © Freudenstein 2024, CC BY-NC. |
When an orchid's capsules dry and split, millions of dustlike seeds are cast to the wind, seemingly with little chance of survival. And yet orchids are said to be one of the most widespread families of flowering plants, both geographically and ecologically! (
Brittanica) Seeds and their strategies are what fascinate me most about orchids, far more than the showy diverse flowers. But this introductory post has gone on long enough. So we will stop here, and let the mystery be for now.
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| "Orchideae" from Ernst Haeckel's Kunstformen der Natur (1899); see source page for names. |
Sources (in addition to links in post)
Brittanica.
Orchid. Accessed May 9, 2026.
Wikipedia.
Orchids. Accessed May 9, 2026.
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