western spotted coralroot

LC - Least Concern

NNR - Unranked

SNR - Unranked

not listed

UPL - Obligate upland

FACU - Facultative upland

FACU - Facultative upland

Western spotted coralroot, also called summer coralroot, is a common, perennial, leafless, rootless, parasitic orchid. It occurs in the United States in the east from Maine to New York, west to northern Minnesota, and in the west from northern Washington and southern California, east to Montana and New Mexico. It also occurs in southern Canada from Nova Scotia to British Columbia, and in Mexico. It is fairly common in northeastern and north-central Minnesota. It is found in moderately moist, upland, mixed and coniferous forests and in conifer plantations. It grows on the ground under mature deciduous trees and sometimes under mature coniferous trees.

Western spotted coralroot is not photosynthetic and does not produce chlorophyll. It obtains all of its nutrients from fungi in the soil (mycotrophic). Instead of roots it has a large, intricately branched, coral-like, underground stem (rhizome). This is the feature that gives the genus its common name. The rhizome is white, deeply buried, and up to 4″ (10 cm) long. The branches are short and stiff, and they have rounded tips. Each branch is capable of giving rise to a flowering stem, but not all of them do.

The flowering stem (scape) is erect, unbranched, hairless, and 6″ to 21⅝″ (15 to 55 cm) in height. It is not bulbous at the base. The color is variable, usually dark and reddish or purplish, sometimes light and brownish-yellow. There are no true leaves. On the lower part of the scape there are 2 or 3 modified leaves (bracts) that surround (sheath) the stem but have no blades. The sheaths are hairless and the same color as the scape. At the top of the stem there is an unbranched, 1¼″ to 6″ (3 to 15 cm) long cluster (raceme) of 6 to 50 conspicuous flowers. Each flower is subtended by a tiny, lance-shaped, 1⁄32″to ⅛″ (1 to 2.8 mm) long bract. These floral bracts are often forked. The flowers bloom from June 10 to July 18, peaking in the last two weeks of June.

Each flower has 3 outer floral leaves (sepals), 3 petals, 1 stamen, and 1 style. The sepals are lance-shaped, directed forward, and 3⁄16″ to ⅝″ (4.7 to 15 mm) long. They have 3 veins and are brown, tan, red, or yellow, often reddish-purple at the tip becoming yellowish at the base. The lateral petals are similar to the sepals but shorter, lighter, usually spotted with purple, and frequently curved inward. The sepals and the lateral petals together form a protective hood over the reproductive column. The lower petal (lip) is white and is usually spotted with purple. There are two small, rounded, lateral lobes near the base. The middle lobe is much larger, 3⁄16″ to 5⁄16″ (4.5 to 8.0 mm) long, ⅛″ to ¼″ (3 to 6 mm) wide. It is egg-shaped, slightly curved downward, and distinctly expanded toward the end. The expanded part of the lobe is more than 1.5 times wider than the base of the lobe. The margin is wavy. The column consists of the style fused to the stalk (filament) of the stamen. It is curved and ⅛″ to 5⁄16″ (3.5 to 7.8 mm) long.

The fruit is an oblong ellipse shaped, ⅜″ to 15⁄16″ (9 to 24 mm) long, 3⁄16″ to ⅜″ (5 to 9 mm) wide seed capsule that hangs loosely downward.

6″ to 21⅝″ (15 to 55 cm)

White spotted with purple

Eastern spotted coralroot (Corallorhiza maculata var. maculata) floral bracts are much smaller, 1⁄64″ to 1⁄32″ (0.5 to 1.0 mm) long. The middle lobe of the lip is 1⁄16″to ⅛″ (1.5 to 4.5 mm) wide and straight sided, more or less uniform in width from the base to the tip. It blooms later, July 1 to August 10, peaking around the middle of July.

Moderately moist, upland, mixed and coniferous forests

June 10 to July 18

Sources

4, 24, 25, 28, 29, 30.

Native

The original spelling of this genus in 1755 was Corallorrhiza, with two “r”s. It was later changed to Corallorhiza with one “r”, a “conserved” name.

Location: Temperance River State Park