Botany Photo of the Day
In science, beauty. In beauty, science. Daily.

January 18, 2017: Botany Photo of the Day is being actively worked on. Returning soon!

Cypripedium parviflorum var. pubescens

Cypripedium parviflorum var. pubescens

Even though the flowering season for the greater yellow lady's slipper is long gone, I'm going to sneak in this out-of-season photograph. I imagine that I'll be sharing a few non-seasonal images from time to time during the winter, just in case your favourite BPotD entries are showy flowers.

This photograph was taken July 20, 2004 in southern Manitoba, several weeks after the normal flowering season should have concluded, thanks to a cool, wet spring and early summer.

If you are familiar with this plant, you may have learned it as Cypripedium calceolus var. pubescens (e.g. University of Wisconsin-Madison species page). The Connecticut Botanical Society succinctly describes why the name has changed, and refers to the account of the Flora of North America project: Cypripedium parviflorum and this particular variety, Cypripedium parviflorum var. pubescens.

Here's a challenge regarding the genus Cypripedium: name the only two states in the lower 48 (excluding the District of Columbia) where you cannot find a member of the genus Cypripedium growing natively. One of the states is very surprising. I think all provinces and territories in Canada have at least one member of the genus (as does Alaska), but I need to check some of the Arctic floras to be certain about Nunavut.

A few recent items of interest regarding Botany Photo of the Day:

  • Tangled Bank Number 39 is up and running on The Questionable Authority weblog. I submitted the recent entry on Acer circinatum to join the collection of roughly two dozen other links to recent science-based writings and images. Well worth the visit to see what other science writers have to offer!
  • There were a couple new comments yesterday on the BPotD entry for the lichen Letharia vulpina. Susanne Alterman, a grad student at the University of California, Santa Cruz, is seeking help collecting specimens from across North America – if you can pitch in, I think your contribution would be greatly appreciated. She has instructions and forms on her site.
  • Back in early May, I was humbled to be able to entertain Dr. Daniel Pauly, his wife and guests from Germany on a tour of UBC Botanical Garden, which I noted in the entry on Philadelphus delavayi. UBC announced two days ago that Dr. Pauly will be the first Canadian to receive the International Cosmos Prize (biography of Dr. Pauly via the Cosmos site). The biodiversity tragedy unfolding in the world's oceans is only being brought to light due to the work of scientists such as Dr. Pauly.

Nature / science resource link: Since we're on the topic of oceans, check out Bone Eating Snot Flower via Deep-Sea News. As you might guess, not a flower, but rather a literal interpretation of the name Osedax mucofloris, a species of zombie worm.


Cypripedium parviflorum var. pubescens Z5 -
RHS Index of Garden Plants, Mark Griffiths

Thanks again, Beverley. I should point out that the Index of Garden Plants is wrong for this plant, since it grows natively in what would be considered a zone 2. I'm not certain whether this is due to Royal Horticultural Society being UK-based and not having a zone 2, or whether Cypripedium calceolus is less hardy than the North American C. parviflorum (is it?). In any case, when it comes to North American natives, a better “zone guide” than books authored overseas is the native distribution of the species. I'm not stating that to disparage the book, but rather just to point out the reality of distant authors canonizing bits of information that disagree with local knowledge. I'm fairly certain that one day Asian and African plant enthusiasts will say the same about what we in North America state for zones about their native plants.

In my writing above, I neglected to mention this tidbit – please don't dig up lady's slippers from native sites and plant them in your garden. In some jurisdictions, they are endangered and / or protected. The only arguable justification is when an area is slated for development and the individuals will be destroyed.

Regarding Cypripedium in Nunavut, I can only say my research has yielded “inconclusive” so far. Apparently, Cypripedium passerinum extends as far north as Churchill, Manitoba, which is about 120km south of the Manitoba / Nunavut border.

Good point about not relying on one source of information for hardiness. It's good to check with local gardeners, nurseries, etc. and if they've had success with a certain plant or if they have any recommendations regarding care. A nursery up the road in Woodland, WA occasionally sells Mexican fan palms (Washingtonia robusta)! When I enquired about hardiness, the woman replied that, with a southern exposure against a warm wall, some people here have had success.


I just want to thank whoever it is that takes the time to do this page. It brightens my day nearly every day. Thanks, and keep up the good work.

You're welcome, Bill. Comments like yours help.

Neither Florida nor Nevada have any native cypripediums. That was an interesting find!

Love the Botany Photo of the Day, and this entire website. Thanks for taking the time to host and maintain it! I will have to look for your trillium photos now! : )

a place of mind, The University of British Columbia

UBC Botanical Garden and Centre for Plant Research
6804 SW Marine Drive, Vancouver, B.C., V6T 1Z4
Tel: 604.822.3928
Fax: 604.822.2016 Email:

Emergency Procedures | Accessibility | Contact UBC | © Copyright The University of British Columbia