Northern Twayblade - Photos Copyright Ward Cameron 2003 - Click to view a larger image Northern Twayblade - Photos Copyright Ward Cameron 2003 - Click to view a larger image Northern Twayblade - Photos Copyright Ward Cameron 2003 - Click to view a larger image Northern Twayblade - Photos Copyright Ward Cameron 2003 - Click to view a larger image 
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Green Flowers ( Orchids )
Orchid Family (Orchidaceae)

Northern Twayblade
Listera borealis

Season: Late June to Late July
Habitat:
 Moist Meadows and Woodlands
Height:
 5-25 cm

Description: Northern twayblade is a perennial herb that has a single pair of egg-shaped leaves and a terminal cluster (raceme) of small, prominently lipped orchid flowers.

Flower: The flowers occur on a sparse raceme of 3 to 15 individual flowers with each borne at the end of a short stalk. The greenish-yellow flowers have five narrow tepals, spreading outward and curving upward. The descending lip is very prominent, extending 8-13 mm with a cleft in the centre of the rounded tip. It has a single furrow that runs up the centre.

Leaf: The leaves usually occur as a single opposite pair, midway up the stem. They are broadly oval or egg-shaped, 1-6 cm long and 0.5 to 3 cm wide. The top surface is glandular hairy.

Fruit/Seed: Egg-shaped, 5mm long capsule.

Similar Species: Broad-lipped twayblade (L. convallarioides) looks similar, but the petals and tepals are tightly recurved, bending backwards and over top of the ovary. The lip is also markedly wider at the tip (wedge-shaped) than the base. It can be found in moist sites throughout the Canadian Rockies. Northwestern twayblade (L. caurina) also has a wedge-shaped lip, but it lacks the notch visible at the tip of the northern and broad-lipped twayblade. Northwestern twayblade is common on the Pacific coast, but less common inland and the Canadian Rockies.

Range: Northern twayblade can be found in the Yukon and Northwest Territories, throughout British Columbia east of the Coast/Cascade Mountains, across Alberta and east to Quebec. Its southern range extends to Oregon, Idaho, Colorado, and Utah.

Notes: The central furrow holds nectar with leads insects towards the stigma. Here a tiny drop of sticky material containing a bundle of pollen gets stuck to their forehead. The pollen will then be deposited on the next twayblade they visit.

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All Material Ward Cameron 2005

 

 

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