Close-up of Calceolaria biflora flower
Species of Calceolaria are variously known as slipperworts, slipper flowers, pocketbook flowers, and lady’s purses. The common names are similar to lady’s slipper orchids or slipper orchids (Cypripedium spp.). Today’s Calceolaria biflora does indeed bear a superficial resemblance to Cypripedium parviflorum, for example, but there are differences. For one, Calceolaria are eudicots while orchids are monocots (see monocots versus “dicots”).
Other differences surround pollination. Cypripedium pollination often employs deception, in that pollinators (typically bees or flies) are enticed to visit the flowers, but rarely is there a pollinator reward. Species of Calceolaria do offer a reward, but not one that is well-known. In most pollinator reward scenarios, the reward is often either nectar or pollen. However, in the case of most species of Calceolaria (including today’s Calceolaria biflora), the reward is floral oil (see Pollination biology in the genus Calceolaria L. (Calceolariaceae) by Sérsic in Stapfia 82). Flowers offering fatty oils as a reward are known to occur in at least 10 plant families, about 80 genera, and 2400 species. Calceolaria with its ~250 species has the most representatives (~200 species) offering fatty oil rewards (statistics from The Ecology of Oil Flowers and Their Bees by the USDA’s Stephen Buchmann). It is also known that oil flowers evolved at least 28 times: The evolution and loss of oil-offering flowers: new insights from dated phylogenies for angiosperms and bees.
Calceolaria biflora is native to Chile and Argentina. Two cultivars, ‘Goldcap’ and ‘Goldcrest Amber’, are listed in the RHS Horticultural Database, so it is sometimes possible to acquire this diminutive taxon. The plant in today’s photograph was photographed in the Trough Courtyard of UBC Botanical Garden two years ago–those plants are dead, but there may be plants from the same accession still alive in the South America section of the Alpine Garden (last verified Feb 2018).
Very interesting post, thanks. My reaction in glancing at the introductory material and photo was: “What?! Has the Orchidaceae been split up?!” (in response to Calceolariaceae). So your first paragraph was perfect 🙂
Calceolaria is from the feminine form of the Latin calceolarius – a shoemaker. A calceolus was a small shoe or half-boot. The Romans did have words for various types of slippers – diabathrum, pedalis, sabatenum, sandalium, soccus (from which we get socks) and solea. Indeed, a diabathrarius was a slipper-maker. Perhaps for once a botanist had mercy on future gardeners and did not coin Diabathraria.
Some Calceolaria from the Andes are invasive weeds, such as Calceolaria tripartita that has been found on Denali in Alaska and in the Himalayas, New Zealand and Norfolk Island.
Though, looking at the selection available from the website of Chileflora, I am tempted by some of those purple ones. I have a walled garden in the middle of a city far from any mountains. Perhaps it would be OK to introduce some.
Wow! I am blown away to learn that there is a whole other realm of pollination ecology – floral oil!
Thanks, Daniel