Counting Calypso orchids

During the last week of May and the first week of June several members of the Kimberley Nature Park Society naturalist group set out to count the Calypso orchids (Calypso bulbosa) that were blooming at that time. We covered as many trails as possible in the Nature Park and in Horse Barn Valley, carefully checking into the bush as far as we could see.

Also known as fairy slippers, the Calypso bulbosa is the only member of this genus of the orchid family. One of the loveliest flowers in the park, Calypso orchids are best seen in May hiding on the mossy forest floor in the shade of the forest canopy. By summer they have disappeared, but in the fall they produce a single parallel-veined, oval leaf atop the bulb which lasts through the winter. Come spring a solitary, showy, fragrant purple orchid appears. This delicate structure grows only in association with a certain species of fungi, which makes it impossible to successfully transplant.

The flower atop the 10- to 25-cm stalk consists of five narrow, twisted petals pointing upward, while the lower petal forms a large slipper spotted with magenta, and a cluster of golden hairs.

Records of counts from previous years show great fluctuations. The first count in 2007 totaled 1,548 blossoms, but in the following four years the count was 540, 433, 1,112, and 1,961 blossoms. This year we found only 426 blossoms.

Why the disparity? Many factors could account for the fluctuating numbers. The first to consider is that this is a citizen’s project, not a rigorous scientific study. Second, not all trails are covered each year. Third, fire interface work in the Park disturbs the forest floor, and more trails have been added with increased use by walkers, runners and mountain bikers. All of these factors could be negatively influencing the habitat of this fragile plant. Although widespread at low- to mid-elevations in forests with abundant leaf mold, this delicate beauty is rapidly being exterminated in populated areas through disturbances such as trampling, picking and land clearing.

Why do we want to find and count this plant in our Nature Park? What does it do for the overall ecology? Maybe nothing. But the joy it brings to observers seeing this touch of beauty concealed on the forest floor is an immeasurable contribution.

Photos by Sherrin Perrouault, Shannon Duncan, Lyle Grisedale and Jim Duncan