Plant Description

Common Name(s):	Stream Orchid
Scientific Name:	Epipactis gigantea
Family:	Orchidaceae (Orchid)
Plant Type:	Perennial
Size:	up to 2 meters
Habitat:	Riparian
Blooms:	April to July
Fire Response:	Germinate from Seed

Epipactis gigantea, a species of orchid, is commonly known as stream orchid or giant helleborine. This wildflower is found along the coast from British Columbia to central Mexico. One of the most abundant orchids of the Pacific coast of North America - we are fortunate to find this plant growing in our Santa Monica Mountains.

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Epipactis gigantea is a perennial ranging in height from 30 centimeters to two meters in height. This plant sheds its leaves and goes dormant at the first sign of drought. The plants I observed had narrowish lance-shaped leaves 5 to 15 centimeters long and two to more than ten amazing orchids per plant. Flowers have three sepals that stick out straight up and left or right which are light brownish or greenish with darker veins, one to two centimeters long. The two top petals are similar in shape and reddish-brown with purple veins. The lowest petal is cup-shaped with a pointed, tongue-like protuberance and is brighter red-brown and more starkly veined, often with areas of yellow. The fruit is a greenish yellow capsule (2 or 3 centimeters long) containing thousands of tiny seeds. The odds of any particular seed taking hold are probably in the same range for an acorn - many thousands of seeds are produced which are unlikely to produce a new plant. This plant grows along streams - hence the name… I saw these in Pt. Mugu State Park on several occasions during the Spring of 2015.

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I found this description of the pollination process in the Electronic Atlas of the Plants of British Columbia fascinating : The Epipactis gigantea is pollinated by flower flies which land on the front half of the lip to sip nectar from the rear half. As the fly leaves, they brush first against the stigma on the underside of the column, then against a gummy flap and finally against the crumbly pollinia- picking up grains of pollen to carry to the stigma of the next flower. Author, Date. Page title. In Klinkenberg, Brian. (Editor) 2015. E-Flora BC: Electronic Atlas of the Plants of British Columbia [eflora.bc.ca]. Lab for Advanced Spatial Analysis, Department of Geography, University of British Columbia, Vancouver. [Accessed: 28/09/2015 9:21:40 AM ]

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Origin of name: From Greek "epipaktis" name for a medicinal plant used by the ancient Greeks. (Source: Pridgeon 1992) Etymology of gigantea From latinized Greek "giganteus" gigantic. (Source: Mayr & Schmucker 1998) Images Botanical Terms for Leaves

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