The stream orchid (Epipactis gigantea) at Filoha Meadows.

A small flower at Filoha Meadows Nature Preserve may be the single most-studied species on a Pitkin County Open Space and Trails property. The locally rare stream orchid (Epipactis gigantea) has been of keen interest since it was first discovered after land purchases in 2001 and 2003 created the Preserve. In-depth monitoring of the plant began in 2018.

The latest assessment of the orchid, conducted in summer 2024 by OST’s botanical/ecological consultant, yielded encouraging news. The density of orchids at Filoha hit the highest level yet recorded. A preliminary monitoring report for 2024 indicates the median density of the orchid along established transects was 88.9 orchid stems per square meter. (Notes: A transect is a line along which the object of study is counted and its occurrences recorded. Median density is a middle value – the point where half of a population density is above it and half is below it. The number of stems does not equate to the number of plants, as a single plant can produce multiple stems.)

Botanical science aside, Filoha’s orchid population last July was astounding to anyone lucky enough to see it. For the general public, tours offered by the Roaring Fork Conservancy each summer are the only way to see the delicate, burgundy-streaked blooms of the stream orchid tucked among the marsh grasses of Filoha’s thermal wetland. Don’t be fooled by gigantea in its name, by the way. The blooms measure an inch or so across. Observers get down on their hands and knees, and peer through a magnifying glass for a better look.

“The orchids were remarkable last summer,” according to Christina Medved, the conservancy’s director of community outreach. She has been leading tours at Filoha for a decade. Last year’s tour participants had a field day – literally and figuratively – spying orchids wherever they looked during a careful visit to the wetland.

“We saw orchids in areas where we haven’t seen them in in the last few years. It was such a treat,” she said.

Also present at Filoha is the even-tinier western bog orchid (Platanthera tescamnis). Specimens of both species have been collected for inclusion at the National American Orchid Conservation Center.

Filoha’s stream orchid population was subject to four consecutive years of study from 2018 through 2021. Then, the monitoring regime switched to every third year, hence 2024’s scheduled assessment. Orchid densities have fluctuated over the years and appear to be affected by various environmental factors, including overall temperature and precipitation in late spring and early summer. Overbank flooding of the Crystal River in 2021 seemed to have aided with a rebounding of orchids along several of the transects.

The stream orchid is a wide-ranging species in western North America, and known to exist in about 30 locations in western Colorado. It occupies habitats near water, including seeps and marshes near hot springs. Throughout its range, it occurs infrequently, but can be locally abundant. It is ranked imperiled in Colorado, based on the relatively small number of its populations.

Open Space and Trails will continue to monitor the Filoha orchids on three-year intervals. Work to control invasive weeds among the orchids will resume this fall with a Roaring Fork Outdoor Volunteers weed pull at Filoha in September. Other potential threats include climate change, its reliance on one type of pollinator and disturbance to the hydrology of its wetland habitat.

While some factors may be beyond Open Space and Trails’ control, the program is committed to protecting these special flowers as best it can.

– ­By Pitkin County Open Space and Trails