Stream Orchid

epipactis gigantea

The Stream Orchid, also known as the giant helleborine, is an elegant and robust wild orchid native to western North America. It stands out in the plant kingdom due to its preference for damp, riparian environments, often gracing the edges of rushing mountain streams, bubbling springs, and wet meadows. Unlike many of its tropical, tree-dwelling relatives, this orchid is terrestrial, anchoring its roots deep into the wet soils and gravel banks of temperate zones.

Habitat: Found in wet habitats such as stream banks, springs, seeps, wet meadows, and moist canyon walls, often growing in sandy or gravelly soil.

Appearance

This species is a tall, leafy perennial growing between 30 to 100 cm in height, featuring lance-shaped, parallel-veined bright green leaves that clasp the sturdy stem. Its flowers, measuring 2 to 3 cm across, hang like delicate lanterns in loose clusters. Each flower boasts a complex color scheme of greenish-yellow sepals and petals heavily veined with reddish-brown, contrasting with a distinct pouch-like, three-lobed lower lip marked with pinkish-purple stripes and a yellow center.

KingdomPlantaePhylumTracheophytaClassLiliopsidaOrderAsparagalesFamilyOrchidaceaeGenusEpipactis

Stream Orchid

Interesting facts

It is one of the few orchid species native to the western United States that can successfully grow directly in active, wet gravel bars.

Its species name 'gigantea' refers to the plant's tall, robust growth form compared to other members of the helleborine genus.

The orchid's nectar is known to contain natural chemical compounds that have a mildly narcotic effect on wasps, making them sluggish and improving pollination success.

Special abilities

Utilizes a tough, creeping network of underground rhizomes to anchor itself firmly into unstable, waterlogged stream banks, preventing erosion.

Produces a specialized sweet nectar containing chemical compounds that mimic aphid alarm pheromones, successfully attracting predatory wasps for pollination.

Forms vital subterranean partnerships with specialized soil fungi to assist its microscopic seeds in germinating and obtaining early nutrients.

Measurements & details

Length: 30-100 cm
Lifespan: 5-20 years

Diet & Feeding

The Stream Orchid is a photosynthesizing plant that produces its own sugars from sunlight, water, and carbon dioxide, while absorbing minerals through its roots.

Age differences: Seedlings rely entirely on nutrients supplied by mycorrhizal fungi before developing green leaves to perform photosynthesis.

Primary Foods

Sunlight
Water
Carbon Dioxide
Nitrogen
Phosphorus
Potassium

Foraging Method

Photosynthesis

Ecological connections

mutualism

Common Western Hoverfly

Syrphus opinator

Provides energy-rich nectar to adult hoverflies, which in turn transfer pollen packets between flowers.

mutualism

Tulasnella Fungus

Tulasnella calospora

Assists the orchid seeds in germination and provides nutrients to the root system.

eaten by

Mule Deer

Odocoileus hemionus

Occasionally grazes on the lush green leaves and juicy stems of the plant in riparian valleys.

Traits

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Also known as

No aliases listed yet.

Collections

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Safety

Danger

1/5 · Very low

No special safety notes yet.

Frequently Asked Questions

How to identify Stream Orchid?

The easiest way to identify Stream Orchid is to use the Snappit nature identifier app.

How long is Stream Orchid?

30-100 cm

How long does Stream Orchid live?

5-20 years

What does Stream Orchid eat?

The Stream Orchid is a photosynthesizing plant that produces its own sugars from sunlight, water, and carbon dioxide, while absorbing minerals through its roots.

Where is Stream Orchid usually found?

Found in wet habitats such as stream banks, springs, seeps, wet meadows, and moist canyon walls, often growing in sandy or gravelly soil.

How does Stream Orchid hunt?

Photosynthesis