''Polemonium pectinatum'' is a species of flowering plant in the phlox family known by the common names Washington Jacob's-ladder and Washington polemonium. It is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found elsew ...

to the state of

Washington Washington commonly refers to: * Washington (state), United States * Washington, D.C., the capital of the United States ** A metonym for the federal government of the United States ** Washington metropolitan area, the metropolitan area centered on ...

in the United States, where it occurs in the Columbia Basin, including the

Channeled Scablands The Channeled Scablands are a relatively barren and soil-free region of interconnected relict and dry flood channels, coulees and cataracts eroded into Palouse loess and the typically flat-lying basalt flows that remain after cataclysmic floods ...

and the

Palouse The Palouse ( ) is a distinct geographic region of the northwestern United States, encompassing parts of north central Idaho, southeastern Washington, and, by some definitions, parts of northeast Oregon. It is a major agricultural area, primaril ...

.''Polemonium pectinatum''.
The Nature Conservancy.

Description

This perennial herb grows from a

taproot A taproot is a large, central, and dominant root from which other roots sprout laterally. Typically a taproot is somewhat straight and very thick, is tapering in shape, and grows directly downward. In some plants, such as the carrot, the taproo ...

, producing a cluster of stems up to 80 centimeters tall. The alternately arranged leaves are each made up of several linear-shaped leaflets up to 5 centimeters long. The hairy, glandular

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. Morphologically, it is the modified part of the shoot of seed plants where flowers are formed o ...

is an open array of white or lavender flowers with five corolla lobes.''Polemonium pectinatum''.
Washington Burke Museum. Flowering occurs in May through July.

Species

This species occurs in

riparian A riparian zone or riparian area is the interface between land and a river or stream. Riparian is also the proper nomenclature for one of the terrestrial biomes of the Earth. Plant habitats and communities along the river margins and banks ar ...

habitat and seasonally moist depressions and bottomlands. Other species in the habitat may include ''

Crataegus douglasii ''Crataegus douglasii'' is a North American species of hawthorn known by the common names black hawthorn and Douglas' thornapple. It is most abundant in the Pacific Northwest. Description ''Crataegus douglasii'' is a compact erect bushy shrub gr ...

'', ''

Amelanchier alnifolia ''Amelanchier alnifolia'', the Saskatoon berry, Pacific serviceberry, western serviceberry, western shadbush, or western juneberry, is a shrub with an edible berry-like fruit, native to North America. Description It is a deciduous shrub or sma ...

'', '' Elymus cinereus'', ''

Rosa woodsii ''Rosa woodsii'' is a species of wild rose known by the common names Woods' rose, interior rose, common wild rose, mountain rose, pear-hip rose, and prairie rose. Distribution and habitat It is native to North America including much of Canada an ...

'', and ''

Ribes aureum ''Ribes aureum'', known by the common names golden currant, clove currant, pruterberry and buffalo currant, is a species of flowering plant in the genus ''Ribes'' native to North America. Description The plant is a small to medium-sized deciduo ...

''.''Polemonium pectinatum''.
Center for Plant Conservation. There are about 26 occurrences of this species, divided into 6 or 7 populations. The plant's total distribution covers less than 2500

acre The acre is a unit of land area used in the imperial Imperial is that which relates to an empire, emperor, or imperialism. Imperial or The Imperial may also refer to: Places United States * Imperial, California * Imperial, Missouri * Imp ...

s. Threats to the species include

overgrazing Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature res ...

, though it can tolerate some grazing activity, being adapted to disturbance. Land use conversion is a threat, for example, the conversion of the Palouse

grassland A grassland is an area where the vegetation is dominated by grasses (Poaceae). However, sedge (Cyperaceae) and rush (Juncaceae) can also be found along with variable proportions of legumes, like clover, and other herbs. Grasslands occur natur ...

s to agriculture. Other threats include alterations in

hydrology Hydrology () is the scientific study of the movement, distribution, and management of water on Earth and other planets, including the water cycle, water resources, and environmental watershed sustainability. A practitioner of hydrology is calle ...

herbicide Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page fo ...

s, and

introduced species An introduced species, alien species, exotic species, adventive species, immigrant species, foreign species, non-indigenous species, or non-native species is a species living outside its native distributional range, but which has arrived there ...

References

External links

{{Taxonbar, from=Q7209293 Polemonium Flora of Washington (state) Flora of North America