Cypripedium passerinum is a species of lady's slipper orchid known by the common names sparrow's-egg lady's-slipper, spotted lady's-slipper, and Franklin's lady's-slipper. It is native to northern North America, where it occurs in Alaska

Alaska

Alaska is the largest state in the United States by area. It is situated in the northwest extremity of the North American continent, with Canada to the east, the Arctic Ocean to the north, and the Pacific Ocean to the west and south, with Russia further west across the Bering Strait...

 and much of western and central Canada, its distribution extending to Quebec

Quebec

Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....

. Its range extends as far south as Glacier National Park in Montana

Montana

Montana is a state in the Western United States. The western third of Montana contains numerous mountain ranges. Smaller, "island ranges" are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...

.

This orchid is a rhizomatous

Rhizome

In botany and dendrology, a rhizome is a characteristically horizontal stem of a plant that is usually found underground, often sending out roots and shoots from its nodes...

 perennial herb growing to a maximum height around 50 centimetres (19.7 in). There are 3 to 7 oval or lance-shaped leaves arranged alternately on the stem, each up to 19 centimetres (7.5 in) long by 6 cm (2.4 in) wide. The herbage is hairy and sticky. The inflorescence

Inflorescence

An inflorescence is a group or cluster of flowers arranged on a stem that is composed of a main branch or a complicated arrangement of branches. Strictly, it is the part of the shoot of seed plants where flowers are formed and which is accordingly modified...

 at the top of the stem contains one or two flowers. The flower has a dorsal sepal

Sepal

A sepal is a part of the flower of angiosperms . Collectively the sepals form the calyx, which is the outermost whorl of parts that form a flower. Usually green, sepals have the typical function of protecting the petals when the flower is in bud...

 covering the petals and two lateral sepals. There are three petals: two flat white petals on either side and one central petal modified into a white or pink-tinged pouch with purplish spotting at the lip and inside, which is said to resemble a sparrow's egg. The fruit is a capsule. The plant may reproduce by seed but it more often reproduces vegetatively

Vegetative reproduction

Vegetative reproduction is a form of asexual reproduction in plants. It is a process by which new individuals arise without production of seeds or spores...

 by sending up more stems from the rhizome.

This species grows farther north than other Cypripedium

Cypripedium

Cypripedium is a genus of 47 species of lady's-slipper orchids native to temperate and colder regions of the Northern Hemisphere.Some grow in the tundra in Alaska and Siberia, which is an unusually cold habitat for orchids. They can withstand extreme cold, growing under the snow and blooming when...

. It grows in moist spruce forests at low elevations, tundra

Tundra

In physical geography, tundra is a biome where the tree growth is hindered by low temperatures and short growing seasons. The term tundra comes through Russian тундра from the Kildin Sami word tūndâr "uplands," "treeless mountain tract." There are three types of tundra: Arctic tundra, alpine...

, dune

Dune

In physical geography, a dune is a hill of sand built by wind. Dunes occur in different forms and sizes, formed by interaction with the wind. Most kinds of dunes are longer on the windward side where the sand is pushed up the dune and have a shorter "slip face" in the lee of the wind...

s, and river terraces, lakeshores, and streambanks. It often grows on calcareous

Calcareous

Calcareous is an adjective meaning mostly or partly composed of calcium carbonate, in other words, containing lime or being chalky. The term is used in a wide variety of scientific disciplines.-In zoology:...

 substrates. It is associated with plants such as white spruce (Picea glauca), Engelmann spruce (P. engelmannii), western redcedar

Thuja occidentalis

Thuja occidentalis is an evergreen coniferous tree, in the cypress family Cupressaceae, which is widely cultivated for use as an ornamental plant known as American Arbor Vitae. The endemic occurrence of this species is a northeastern distribution in North America...

 (Thuja occidentalis), red-osier dogwood (Cornus sericea), willows (Salix spp.), horsetail (Equisetum spp.), longtube twinflower (Linnaea borealis), sedges

Carex

Carex is a genus of plants in the family Cyperaceae, commonly known as sedges. Other members of the Cyperaceae family are also called sedges, however those of genus Carex may be called "true" sedges, and it is the most species-rich genus in the family. The study of Carex is known as...

 (Carex spp.), one-sided pyrola (Pyrola secunda), and moss carpet (Pleurozium schreberi).

External links

• USDA Plants Profile