Species distinguishing characteristics:
- Basal rosette of variegated evergreen leaves with a white midvein
- Single, leafless stem with glandular hairs on the upper portion
- Greenish-white, stalkless flowers in 1-sided clusters
- Flowers have a hood, a short, pouch-like lip, and 2 flaring sepals
- Found in well drained humus of shady coniferous forests
- Clusters of flowers (occasionally singly) with 3 sepals and 3 petals
- Lowest petal of each flower forms a flared or pouch-like lip
- Fruit is a dry capsule with millions of tiny seeds
- Leaves simple, alternate, and stalkless
- Largest family of flowering plants - includes vanilla orchids (Vanilla spp.), whose pods provide vanilla flavoring
Erect perennial, 10–45 cm tall, with evergreen leaves.
Leaves and stems:
A single, stout, scaly, leafless stem, with glandular hairs on the upper portion, arises from a ground-hugging basal rosette of thick, dark, glossy green variegated leaves. The basal rosette usually has more than 2 alternate leaves, 3–8 cm long, that are narrowly oval with a pointed tip. Leaves have winged stalks. The intensity of the striking, diamondback pattern on leaves varies from having many fine, white, lateral veins to having white only along the midvein.
3 to 30 (most often 10–15) greenish-white, stalkless flowers in a dense, long, narrow flower cluster at the stem tip. Flower clusters, 6–12 cm long, are downy haired and have most of the flowers oriented to one side, or flowers attached in a spiraling pattern. Each flower, 1.5–2 cm long, has a hood, 5–9 mm long, composed of 2 fused petals and an upper sepal, and a shorter, beaked, pouch-like lower lip petal. Two lower sepals flare outward. Flowers connect to the stalk by a twisted ovary and subtend by a scale-like bract. Plants may lack a flowering stalk as not all plants bloom each year.
Short, slender, creeping rhizomes and thick, fibrous roots. Spreads primarily by reproduction from rhizomes.
Erect to ascending capsules, about 1 cm long, that have hundreds of tiny, filament-like seeds.
Rich, moist, well-drained soils of dense, shady, coniferous forests at low elevations to lower subalpine elevations.
Despite its diminutive size, giant rattlesnake-plantain is an important food plant for white-tailed deer (Odocoileus virginianus) and woodland caribou (Rangifer tarandus). White-tailed deer in the Swan Valley (NW Montana) have been observed eating giant rattlesnake-plantain in winter. Bumblebees (Bombus spp.) are the most common pollinators of the giant rattlesnake-plantain. Pollination occurs when bees move from the younger male flowers, found at the top of one flower cluster, to older female flowers, found near the bottom of another flower cluster. While some orchid flowers lack nectar, giant rattlesnake-plantain contains nectar, which encourages repeat visits by pollinators and increases chances for successful pollination.
Like many orchids, mycorhizzal fungi in the soil allow the plant to obtain sufficient nutrients. These symbiotic fungi are sensitive to soil compaction, fertilizer, and fungicides. The loss of associated fungi during transplantion inhibits the ability to transplant wild orchids, such as giant rattlesnake-plantain, successfully. This species may have enough leaf area at maturity to make it nearly independent of its mychorrhizal partners.
The plant, fresh or dried, is mucilaginous and astringent, and useful as a drawing poultice for insect bites and inflammations of the skin, much like the non-native plantain (Plantago major), a plant with a similar rosette that was widely used by early settlers. The “doctrine of signs” that guided the application of herbal medicines in this era dictated that plants would resemble the malady they treated. This explains the rest of the plant’s name and the belief that the leaves could treat snakebites. Some native tribes used the roots as medicine for childbirth, and a tea of the leaves to soothe sore throats and coughing. Children in Northwest Coastal tribes rubbed the leaves together to separate the layers and then blew through the stem to inflate them like balloons.