Cypripedium candidum (Small White Lady’s Slipper)

The conservation status of Cypripedium candidum, the small white lady’s slipper, is currently ranked as S1 (critically imperiled) by the Missouri Natural Heritage Program.

I have one more lady’s slipper we found in May to share. Cypripedium candidum or small white lady’s slipper requires moist and full-sun exposures, such as may be found in wet prairies, meadows, fens and forest edges. The reason for its rare status (likely found on fewer than five locations in the state) is due to habitat disturbance and orchid poachers digging them up for horticultural uses.

A small bunch of small white lady’s slippers

This species can hybridize with C. parviflorum (yellow lady’s slipper) when found in close proximity. This can potentially be a conservation concern in some states, but to my knowledge, there are no close associations between these two species in Missouri.

The habitat where these slippers where found in Shannon County, MO. You will not be able to see them, but I assure you, there are slippers in this photo.

It was wonderful finding this and the other lady’s slippers in the state this year. I’m hoping this one can still be found here far into the future.

The rare Cypripedium candidum

OZB

Cypripedium parviflorum (Yellow Lady’s Slipper)

A fresh Cypripedium parviflorum photographed in late May in St. Francois County, Missouri.

May was definitely a lady’s slippers month. My friends and I found four species within a week (three in MO, 1 in AR). Of the three species found in Missouri, two are species of conservation concern within the state – Cypripedium candidum, small white lady-slipper (S1) and C. reginae, showy lady-slipper (S2S3). I’ve shared photos of C. reginae on this blog before and a C. candidum post will be coming shortly.

I’ve posted photos of C. parviflorum (yellow lady’s slipper) here before as well but these accompanying photos were taken at a new location for me in St. Francois County. Some taxonomists, books and keys have this species split into two varieties – C. parviflorum var. pubescens, or the “greater” yellow lady’s slipper and C. parviflorum var. makasin, the “small” yellow lady’s slipper. Some authors have even split these two into specific status while even others have argued there is no basis in splitting these into varieties. From my limited experiences with these in Missouri and the taxonomic descriptions I have read, I have not seen ample evidence to suggest these should be split into varietal forms. There seems to be a lot of variation in the characteristics that are supposed to describe these two varieties and until someone shows me better proof that these should be treated as two separate forms, all I can say is that, “I’m from Missouri” and I will not be including these as two in my “master list” of the Missouri orchids.

If you are knowledgeable in this area and wish to argue, by all means, please let me know.

A very nicely patterned Cypripedium parviflorum.

-OZB