Calypso orchid (Calypso bulbosa). Photo courtesy of Tom Gibson.

Phenology spotlight: calypso orchid

May 18, 2016

Fred Case starts his description of calypso orchid (Calypso bulbosa) in Orchids of the Western Great Lakes Region, saying "No other northern orchid has so captured the imagination of flower lovers as calypso!" This may well be true. Last year, four separate groups of botanists (myself included) trekked to a forest in southern Douglas County, looking for a single calypso population. This elusive beauty evaded us all, only strengthening its hold on the botanical imagination.

The name "calypso" has Greek roots, meaning "to conceal" or "to hide." In Homer’s Odyssey the sea-nymph Calypso kept Odysseus captive on her island for several years. As this group of disappointed botanists came to know firsthand, there is a reason the diminutive wildflower is called calypso orchid. In 2015, it lived up to its name.

Calypso orchid is also deceptive in its pollination strategy. For the one or two week flowering window in late May, it produces no nectar and therefore offers no reward to visiting bumblebees, its main pollinator. As the bee searches deep in the orchid flower for any morsels of sweetness, it picks up the sticky pollinarium and carries it to the next calypso flower. The bees quickly wise up, leading most calypso orchids unpollinated. The ones that are, though, produce huge amounts of seed, which keep the population going. It’s a strange pollination strategy.

Calypso is phylogenetically unique also. It is monotypic, meaning there is only one species in the genus – putty root orchid (Aplectrum hyemale) is another example of a monotypic orchid. In these boreal habitats, it can be found in one of two habitat types. In Wisconsin it is limited to cool, moist conifer forests dominated by white cedar and black spruce. These habitats are often blanketed with a thick mat of moss, but if you’re looking for calypso, focus on the moss-free areas at the base of trees in spruce or cedar needle litter. However, on Isle Royale and elsewhere in its range calypso can also be found in drier situation such as sandy forested ridges under balsam fir and white cedar.

News archive