Varieties of Calypso bulbosa in North America

Calypso bulbosa was described in 1842 by William Oakes (it was previously described by Linnaeus as Cypripedium bulbosum). It grows a single leaf in the fall which persists through winter and then withers away just after flowering in late spring. In the spring it produces a single, (or very rarely two) pink (or rarely white) slipper-shaped flower. Surprisingly, it is not related to other slipper orchids but is instead a close relative of orchids such as Corallorhiza, Tipularia, and Aplectrum. The species is distributed throughout North America, as well as much of Europe and Asia. In North America there are two varieties and one hybrid variety of Calypso bulbosa, C. bulbosa var. americana, C. bulbosa var. occidentalis and C. bulbosa nothovar. kostiukiae (a naturally occurring hybrid between the previous varieties). Luckily, The varieties are actually quite easy to identify once you know what to look for.

Calypso bulbosa var. occidentalis:
This variety is found (as its name suggests) mostly on the west side of North America (a plant I found near my home in Bozeman, MT is the most easterly observation on iNaturalist to date). It has numerous maroon spots on the lamina (the blade like top of the labellum) and the “beard” (likely false anthers to attract bees) is white (or very pale pink) and sparse. Another (though rather redundant) method of identifying this variation is by the lamina, it is usually slightly shorter than the horns (likely false nectar spurs) whereas in C. bulbosa var. americana the lamina is about the same length or a little longer.


Calypso bulbosa var. occidentalis showing off its numerous spots and lack of a yellow “beard”

Calypso bulbosa var. americana:
This variety has a much larger range than C. bulbosa var. occidentalis, it can be found from the east coast of the United States and Canada to Alaska and south to Arizona and New Mexico. It has a thick yellow beard and no significant spots on the labellum (there are actually usually about four spots nestled in the beard).


Calypso bulbosa var. americana Note the yellow “beard” and absence of maroon spots on the labellum.

Calypso bulbosa nothovar. kostiukiae:
Found anywhere the ranges of C. bulbosa var. americana and C. bulbosa var. occidentalis overlap. It has both a thick yellow “beard” and many spots on the labellum. This is probably my favorite variety of Calypso bulbosa not only because it looks nice but also because it is one of the few naturally occurring hybrids in Montana.


Calypso bulbosa nothovar. kostiukiae showing distinctive combination of spots and a yellow “beard”.

That other variation (form?):
I have seen this odd form on two separate occasions, it has neither spots or a yellow beard. My first instinct was to think it was an aberrant flower, but one of the plants has bloomed the same way two years in a row (I only found the other one last year so I have yet to see it bloom a second time). My best guess is that it is either a spotless form of C. bulbosa var. occidentalis (or a beardless form of var. americana?) or a double recessive C. bulbosa nothovar. kostiukiae. Both plants were found near C. bulbosa nothovar. kostiukiae.


An unidentified variety of Calypso bulbosa after consulting @juancerda and @arethusa, I am fairly confident this is C. bulbosa var. americana.

Hopefully you have found this helpful or at least entertaining,
happy orchid hunting!

Posted on March 11, 2019 02:43 AM by afid afid

Observations

Photos / Sounds

What

Kostiuk's Hybrid Calypso (Calypso bulbosa × kostiukiae)

Observer

afid

Date

May 2018

Description

A group of Calypso bulbosa nothovar. kostiukiae (C. bulbosa var. occidentalis x C. bulbosa var. americana) showing characteristic spots and yellow beard.

Photos / Sounds

What

Eastern Fairy-Slipper (Calypso bulbosa var. americana)

Observer

afid

Date

May 2017

Description

An unusual form of calypso bulbosa. I suspect this might be a double recessive form of C. bulbosa var. kostiukiae that is lacking both spots and yellow fuzz.

Tags

Photos / Sounds

What

Eastern Fairy-Slipper (Calypso bulbosa var. americana)

Observer

afid

Date

May 2018

Tags

Photos / Sounds

What

Fairy-Slipper (Calypso bulbosa)

Observer

afid

Date

May 2018

Comments

Nice!

Posted by milletman about 5 years ago

Great!

Posted by denilsonoz about 5 years ago

Thanks! I enjoyed writing it!

Posted by afid about 5 years ago

This is very helpful - very clear identification of what to look for, and really good pix showing them. Thanks much!

Posted by kitkestrel about 5 years ago

Spectacular! I really enjoyed this. :)

Posted by sambiology about 5 years ago

Very nice—quite informative with beautiful photography.

Posted by arethusa about 5 years ago

Thanks everyone!!

Posted by afid about 5 years ago

Great article @afid!. WIth respect to the white lipped C. bulbosa. It is most likely a mutant C. bulbosa americana that just happens to have lost the yellow pigmentation. I have seen some images of plants similar to yours in areas where var occidentalis is not found. Here are two links with observations that also include Calypso lacking yellow pigmentation.

https://www.flickr.com/photos/ab_orchid/15008923179

http://www.plantsinusa.com/show/plant/Fairy-Slipper/15653

One thing I should clarify is that C. bulbosa americana does have a few spots scattered in the "bearded" area but not the lip blade which is why you are able to identify this white lip mutant as var. americana. X kostiukiae will show more porminent spots on the lip blade.

Amazing article, very informative article and the images are just breathtaking!

Posted by juancerda about 5 years ago

Thanks @juancerda I couldn't find any information on the odd variety so I really appreciate your insight!

Posted by afid about 5 years ago

Excellent article and great find of what I agree is an aberrant form of v. americana. Thanks for the message on my blog. I joined iNaturalist some years ago but never did anything on it.

Posted by ronaldhanko almost 5 years ago

Thanks @ronaldhanko

Posted by afid almost 5 years ago

Very helpful.
I can see why Calypso bulbosa nothovar. kostiukiae is a favorite. Beautiful.

Posted by sentraevant over 4 years ago

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