Polemonium occidentale
Encyclopedia
Polemonium occidentale is a species of flowering plant in the phlox family
known by the common name western Jacob's-ladder. There are two subspecies. The common ssp. occidentale is native to western North America from British Columbia
to Colorado
to California
, where it can be found in moist areas of many habitat types, including meadows and woodlands. There is also a rare subspecies, ssp. lacustre, which is known only from a total of three counties in Minnesota
and Wisconsin
, and is found only in white cedar
swamp
habitat there.
This is a rhizomatous
perennial herb producing an erect stem up to one meter tall. The leaves are located along the stem, each divided into many small lance-shaped leaflets. The inflorescence
is an open, elongated array of several bell-shaped, five-lobed flowers each up to 1.5 centimeters long. The flower corolla is blue to bright purple with a white throat.
The rare ssp. lacustre faces threats including peat mining
in its swamp habitat, herbivory by deer
, and alterations in the local hydrology
where it grows. There are only five populations of this subspecies.
Polemoniaceae
Polemoniaceae are a family of about 25 genera with 270-400 species of annual and perennial plants, native to the Northern Hemisphere and South America, with the center of diversity in western North America, especially in California.Only one genus is found in Europe, and two in Asia, where they...
known by the common name western Jacob's-ladder. There are two subspecies. The common ssp. occidentale is native to western North America from British Columbia
British Columbia
British Columbia is the westernmost of Canada's provinces and is known for its natural beauty, as reflected in its Latin motto, Splendor sine occasu . Its name was chosen by Queen Victoria in 1858...
to Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
to California
California
California is a state located on the West Coast of the United States. It is by far the most populous U.S. state, and the third-largest by land area...
, where it can be found in moist areas of many habitat types, including meadows and woodlands. There is also a rare subspecies, ssp. lacustre, which is known only from a total of three counties in Minnesota
Minnesota
Minnesota is a U.S. state located in the Midwestern United States. The twelfth largest state of the U.S., it is the twenty-first most populous, with 5.3 million residents. Minnesota was carved out of the eastern half of the Minnesota Territory and admitted to the Union as the thirty-second state...
and Wisconsin
Wisconsin
Wisconsin is a U.S. state located in the north-central United States and is part of the Midwest. It is bordered by Minnesota to the west, Iowa to the southwest, Illinois to the south, Lake Michigan to the east, Michigan to the northeast, and Lake Superior to the north. Wisconsin's capital is...
, and is found only in white cedar
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...
swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...
habitat there.
This 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 producing an erect stem up to one meter tall. The leaves are located along the stem, each divided into many small lance-shaped leaflets. 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...
is an open, elongated array of several bell-shaped, five-lobed flowers each up to 1.5 centimeters long. The flower corolla is blue to bright purple with a white throat.
The rare ssp. lacustre faces threats including peat mining
Peat
Peat is an accumulation of partially decayed vegetation matter or histosol. Peat forms in wetland bogs, moors, muskegs, pocosins, mires, and peat swamp forests. Peat is harvested as an important source of fuel in certain parts of the world...
in its swamp habitat, herbivory by deer
Deer
Deer are the ruminant mammals forming the family Cervidae. Species in the Cervidae family include white-tailed deer, elk, moose, red deer, reindeer, fallow deer, roe deer and chital. Male deer of all species and female reindeer grow and shed new antlers each year...
, and alterations in the local hydrology
Hydrology
Hydrology is the study of the movement, distribution, and quality of water on Earth and other planets, including the hydrologic cycle, water resources and environmental watershed sustainability...
where it grows. There are only five populations of this subspecies.