This small perennial orchid produces a low rosette of evergreen basal leaves. Individual leaves are 1½-2½” long and ¾-1½” across; they are ovate or broadly elliptic and smooth along their margins. There are 5-7 primary veins per leaf; they are parallel. These veins are interconnected through a network of secondary veins. Both the primary and secondary veins are accented in white, while the remaining leaf surface is dark green. The basal leaves taper abruptly to petiole-like bases that are short and winged, where they are also accented in white along their central veins. After several years, a spike-like raceme of flowers develops from the basal rosette that is 4-14″ tall and more or less erect. The central stalk of this inflorescence is light green, glandular-pubescent, and terete. Along the lower two-thirds of its length, there are widely separated leafy bracts. These bracts are small in size (about ½” in length), linear-lanceolate in shape, and ascending to erect. Along the upper one-third of the central stalk, the small flowers are densely distributed, facing in all directions.
Cultivation: The preference is medium shade to dappled sunlight, mesic to dry-mesic conditions, and an acidic loose soil that contains loam, loess (wind-blown silt from a prior ice age), or glacial till with decaying organic matter. The site should be protected from drying winds and it should be relatively humid. The root system of this orchid benefits from an endomycorrhizal association with certain kinds of fungi. This orchid has been successfully cultivated indoors in terrariums (Ugiansky, 2010). It should not be collected from the wild, which can easily destroy local populations.
Range & Habitat: The native Downy Rattlesnake-Plantain is uncommon in Illinois, occurring mostly in northern and southern Illinois (see Distribution Map). Habitats include upland woodlands, north-facing wooded slopes, bluffs, large wooded ravines or sandstone canyons, sandstone glades, and woodlands damaged by logging. On rare occasions, this orchid has also been found in forested bogs. It is often associated with such canopy trees as oaks, pines, Eastern Hemlock (Tsuga canadensis), or sugar maple (Acer saccharum). This orchid usually occurs in high quality natural areas.
Faunal Associations: The small flowers are cross-pollinated by bees, including bumblebees (Bombus spp.) and green metallic bees (e.g., Augochlora spp., Augochlorella spp.); see ILPIN and Homoya (1993) for more information. Aside from this, little is known about floral-faunal relationships for this orchid. The evergreen leaves may be browsed by deer and the rhizomes may be eaten by chipmunks or mice, but additional study of such potential threats is required.
Photographic Location: A rocky bluff dominated by Eastern Hemlock (Tsuga canadensis) at a nature preserve in east-central Indiana.
Comments: While the flowers of Downy Rattlesnake-Plantain are rather small, the reticulated patterns of its basal leaves are very ornate and unique, making this orchid easy to identity. In spite of its common name, this orchid is not closely-related to plantains (Plantago spp.); its leaves have a shape that is similar to some of the common broad-leaved plantains. The common name is also inspired by the superficial resemblance of the leaves’ reticulated patterns to the skin of a rattlesnake. The inflorescence of Downy Rattlesnake-Plantain resembles those of the Lady Tresses’ Orchids (Spiranthes spp.), although they have dissimilar leaves. The flowers of the former orchid differ from those of the latter by the pouch-like structure of their lower lips, which is lacking in the flowers of Lady Tresses’ Orchids. There are other orchid species in the Goodyera genus, but their ranges are located outside of Illinois, mostly to the north or northeast.