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Western Coralroot Back to Plant Page
Corallorhiza mertensiana

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About Western Coralroot (Corallorhiza mertensiana) Corallorhiza mertensiana, or Pacific coralroot, is a coralroot orchid native to the shady conifer forests of northwestern North America. It also goes by the common names Western coralroot and Mertens' coralroot. Corallorhiza mertensiana was previously considered a subspecies of Corallorhiza maculata but was given species rank in 1997 by Freudenstein. Corallorrhiza mertensiana is a leafless, parasitic, perennial orchid that is 6-20 inches tall. The stem is red to brownish purple. The upper petals are pink to reddish pink, with yellow to dark red veins. The lower petals are wider, dark pink to red, and have three deep red veins. Beneath the lower petal the spur is prominent. The flower spikes are visible from May to August. Corallorrhiza mertensiana has no roots, only hard, branched rhizomes that resemble coral. Fungal Associations. Corallorrhiza mertensiana is a nonphotosynthetic, myco-heterotroph that receives its nutrition from ectomycorrhizal fungi. The fungi receive mineral nutrients and carbon symbiotically from trees. Corallorrhiza mertensiana parasitizes the carbon from the fungi. Corallorrhiza mertensiana only associates with mutually exclusive subsets of species from the Russulaceae. Corallorrhiza mertensiana never shares fungal species with Corallorrhiza maculata even when intermixed at the same growing site. Habitat and Distribution. Corallorrhiza mertensiana grows in shady coniferous forests at low to mid-elevations. It prefers damp soil that is rich in humus, and receives dappled sunlight. Corallorrhiza mertensiana is found in the Cascades from Alaska to California, and the Rocky Mountains from Alberta to Wyoming. In a survey of the plants found in Glacier Bay, Alaska in 1923, Corallorhiza mertensiana was reported to be growing beneath the thickets of Alnus tenufolia along with Petasites frigida, Aspidium, and Polystichum. In British Columbia is has been found to be associated with Gaultheria shallon, Hylocomium splendens, and Rhytidiadelphus loreus.
Plant Description
Plant Type
Perennial herb

Max. Height
0.5 - 1.7 ft (0.15 - 0.5 m)

Flower Color
Pink, Yellow, Purple, Red, Brown

Native Status

Natural Setting
Elevation ?
88' - 6950'

Annual Precip. ?
44.1" - 150.3"

Summer Precip. ?
0.75" - 5.46"

Coldest Month ?
33.6° F - 46.1° F

Hottest Month ?
51.9° F - 70.2° F

Humidity ?
0.01 vpd - 20.52 vpd

Landscaping Information
Nursery Availability
Never or Almost Never Available

Other Names
Common Names
Pacific Coralroot, Mertens' Coralroot

Sources include: Wikipedia. All text shown in the "About" section of these pages is available under the Creative Commons Attribution-ShareAlike License. Plant observation data provided by the participants of the California Consortia of Herbaria, Sunset information provided by Jepson Flora Project. Propogation from seed information provided by the Santa Barbara Botanical Garden from "Seed Propagation of Native California Plants" by Dara E. Emery. Sources of plant photos include CalPhotos, Wikimedia Commons, and independent plant photographers who have agreed to share their images with Calscape. Other general sources of information include Calflora, CNPS Manual of Vegetation Online, Jepson Flora Project, Las Pilitas, Theodore Payne, Tree of Life, The Xerces Society, and information provided by CNPS volunteer editors, with special thanks to Don Rideout. Climate data used in creation of plant range maps is from PRISM Climate Group, Oregon State University, using 30 year (1981-2010) annual "normals" at an 800 meter spatial resolution.

Links:   Jepson eFlora Taxon Page  CalPhotos  Wikipedia  Calflora

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