Yellow Lady’s Slipper – Like Winning the Lottery

The existence of Yellow Lady’s Slipper (Cypripedium parviflorum) orchids is like winning the lottery, on so many levels.  Their bright yellow moccasin shaped petals, complemented by deeply veined lush green leaves, are strikingly beautiful.

Yellow Lady's Slipper (Cypripedium parviflorum) orchids

Yellow Lady’s Slipper (Cypripedium parviflorum) orchids

Yellow Lady’s Slipper uses its showy floral display to entice bees to assist in its pollination.  In addition to the bright yellow pouch, the flowers have two more petals, one on each side of the slipper, usually twisted, with striping varying from green to dark maroon or purple.  They look like they should be the ties that would be used to keep the slipper on a lady’s foot.  The sepals, which can be seen above and below the back of the slipper, resemble the petals.  Together, they create a display designed to entice potential pollinators.

Yellow Lady's Slipper (Cypripedium parviflorum)

Yellow Lady’s Slipper (Cypripedium parviflorum)

Bees visit flowers in the expectation of a food reward in the form of nectar, or pollen, or both.  Yellow Lady’s Slippers don’t produce nectar, so pollen is the only possible reward.  Once a bee has discovered the flower, more direction is provided.  At the back of the opening to the slipper, there is a triangular structure dotted with maroon, pointing downward.  This advertisement is the kind of sign the bee is expecting, promising it a reward if it enters the slipper.

Yellow Lady's Slipper (Cypripedium parviflorum)  Note the shield-shaped 'nectar' guide at the back of the flower

Yellow Lady’s Slipper (Cypripedium parviflorum) Note the shield-shaped ‘nectar’ guide at the back of the flower

There is maroon-purple striping inside the slipper, pointing to the reproductive parts of the flower, with gland-tipped hairs nudging the bee toward the receptive female flower part (the stigma) first.  If the bee has already visited a compatible flower, pollen will be scraped off and deposited, fulfilling the bee’s role in the pollination process.  The bee must then pass by the anther, the male flower part where the pollen is found.  In many flowers, this would be the bee’s payback.  The bee would be able to harvest pollen to bring back to its nest to feed its offspring.  But all of the pollen grains of a Yellow Lady’s Slipper’s anther, of which there are thousands, are packed together in a single pollinium, which is attached to the bee as it passes the anther, preparing to exit the flower.  The pollen grains are not available to the bee to harvest for its own use.  The bee has been duped!  The flower advertised falsely, and the bee leaves without a reward.

Yellow Lady's Slipper (Cypripedium parviflorum)  Note the maroon striping inside the 'slipper'.

Yellow Lady’s Slipper (Cypripedium parviflorum) Note the maroon striping inside the ‘slipper’.

It is usually a medium sized bee, possibly a Little Carpenter, Halictid, Mason or Andrenid, that successfully navigates a Yellow Lady’s Slipper, since the pollinator must be small enough to fit through the flower’s exit hole.  If the bee is too large, it may be trapped inside the flower.

Perhaps not surprisingly, successful pollination does not often occur.  (How many bees are gullible enough to fall for the false advertising twice, the minimum number of times necessary to achieve pollination?  Probably not that many.)  So Yellow Lady’s Slipper makes every successful pollination event count, enabling fertilization of thousands of ovules in the plant that receives them.

The result is a fruit capsule that contains thousands of tiny, dust-like seeds that are wind dispersed through slits in the capsule.  But only a small percentage of the seeds find their way to a location that is hospitable to the plant.  The presence of the right mycorrhizal fungus in the soil is especially important, since it is only through the fungus that the orchid is able to obtain the nutrients it needs to survive.  Even if the seed finds the right conditions to establish itself, it can take ten years or more to be mature enough to produce a flower.

Yellow Lady's Slipper (Cypripedium parviflorum)  fruit capsule

Yellow Lady’s Slipper (Cypripedium parviflorum) fruit capsule

Yellow Lady’s Slipper is fairly widespread, but not common, and is considered threatened or endangered in some states.  This lovely orchid can be found in a variety of habitats, from woodland understory to meadows and bogs, primarily in the eastern United States (excluding Florida), the Rocky Mountain states, most Canadian provinces, and even Alaska.

If you see it, you know you’ve won the lottery.

Yellow Lady's Slipper (Cypripedium parviflorum)

Yellow Lady’s Slipper (Cypripedium parviflorum)

 

Note:  There are three varieties of Yellow Lady’s Slipper.  The most common is Greater Yellow Lady’s Slipper (Cypripedium parviflorum var. pubescens).  Cypripedium parviflorum var. makasin is often, but not always, smaller, and may have a musty scent.  It can be found in the northern part of the range.  Lesser Yellow Lady’s Slipper (Cypripedium parviflorum var. parviflorum) tends to be smaller, and has more consistently dark markings on the lateral petals and sepals.  It’s range is more southern.

Resources

Eastman, John.  The Book of Forest and Thicket.  1992.

Gracie, Carol.  Spring Wildflowers of the Northeast. 2012.

Willmer, Pat.  Pollination and Floral Ecology.  2011.

Flora of North America

Illinois Wildflowers

USDA Plants Database

USDA Forest Service

 

 

An Orchid in Winter

On a walk in the woods the other day, I found what I was looking for: a leaf!   It may seem like it should be pretty easy to find a leaf on the forest floor, but I was looking for something very specific, not a fallen leaf, but the newly unfurled leaf of a native orchid called Puttyroot (Aplectrum hyemale).

Puttyroot (Aplectrum hyemale) leaf

Puttyroot (Aplectrum hyemale) leaf

Hyemalemeans winter, a reference to the fact that the leaves of this plant emerge in late November or December and are visible until spring.  Puttyroot is found in rich deciduous woodlands, often in the company of Sugar Maple (Acer saccharum) and American Beech (Fagus grandifolia).  It gathers its energy from the sun during the months when the forest canopy is open, while the leaves are off the trees.  Photosynthesis occurs in this plant at temperatures as low as 35ºF (2ºC).  During this time, Puttyroot also benefits from the nutrients released to the soil from the blanket of decomposing leaves from the neighboring trees.

In ideal conditions, Puttyroot sends up a single striped, accordion-pleated leaf in late fall, about 3-8 inches (.75 – 2 dm) long and 1-3 inches (.25 – .75 dm) wide. The leaf dies back by the time the single flower stalk blooms in May or early June.  The flower stalk height can vary from about 6 to 20 inches (1.5 – 5 dm).

Puttyroot (Aplectrum hyemale) flowers

Puttyroot (Aplectrum hyemale) flowers

Bees are likely the pollinators of Puttyroot, although the flowers can also self-fertilize if necessary.  Puttyroot’s many tiny seeds are dispersed by the wind.

Puttyroot (Aplectrum hyemale) flower

Puttyroot (Aplectrum hyemale) flower

There may be years when a Puttyroot plant doesn’t bloom, its presence only revealed by the winter leaf.  Some years the plant may be completely dormant, without even the leaf visible above ground.

This orchid species is native throughout the eastern half of the United States (except Florida) and in Quebec and Ontario provinces in Canada, but it is listed as rare, threatened or endangered throughout much of its range, including New York, New Jersey, Pennsylvania, Vermont and Massachusetts.

Non-native, invasive plants like Garlic Mustard (Alliaria petiolata) and Japanese Stiltgrass (Microstegium vimineum) are a serious threat to Puttyroot and its companion woodland plants. Not only do these invasive species compete for resources with native plants, they also alter the soil chemistry in a negative way, interfering with the mycorrhizal fungi that is present.  Most plants don’t get the nutrients they need directly from the soil, but rather through a partnership with mycorrhizal fungi.  Plants provide sugars to the fungi, and the fungi in turn make nutrients available to the plants. If the fungi aren’t present, the plants won’t get the nutrients necessary to continue to be viable.  The good news is that both Garlic Mustard and Japanese Stiltgrass are easy to remove by pulling.  Garlic Mustard is edible, so you can reward yourself for removing it by eating your ‘harvest’.  Garlic Mustard pesto, anyone?

Early settlers used a mucilaginous substance obtained from Puttyroot’s corms (part of the underground food storage system) to repair broken pottery, a practice that resulted in the plant’s common name.  Another common name, Adam and Eve, also refers to the plant’s corms, which are usually paired.

Puttyroot (Aplectrum hyemale) leaf

Puttyroot (Aplectrum hyemale) leaf

Go for a walk in the woods and see if you can find a Puttyroot leaf.  If you’re successful, make a mental note of its location.  Then visit the spot again in May or June, to see if you can find the flower stalk in bloom.  Repeat the process until you find this buried treasure!

Resources

Capon, Brian.  Botany for Gardeners.  2005

USDA Plants Database

Go Botany

New England Plant Conservation Program Aplectrum hyemale (Muhl. ex Willd.) Nutt. Puttyroot

Illinois Wildflowers

USDA National Invasive Species Information Center:
Garlic Mustard
Japanese Stiltgrass