Cardamine constancei

Constance's bittercress has an erect, unbranched stem ranging from {{cvt|1|to|1.5|mm}} in diameter; it ranges from glabrous to sparsely hairy. It has four to seven cauline leaves that are typically ovate in shape with serrated edges and a cuneate base. Leaves range from {{cvt|5|to|13|cm}} in length and {{cvt|20|to|65|mm}} in width. The flowers are pink or white with oblanceolate petals that range from {{cvt|15|to|28|mm}} in length and {{cvt|5|to|8|mm}} in width. The fruits are linear and {{cvt|2.5|to|3.5|cm}} in length and {{cvt|1.9|to|2.1|mm}} in width.{{Cite web |title=Cardamine constancei |url=https://swbiodiversity.org/seinet/taxa/index.php?taxon=Cardamine+constancei&formsubmit=Search+Terms |access-date= |website=SEINet Portal Network}}

The plant flowers from May to June.{{Cite web |title=Cardamine constancei in Flora of North America (Vol. 7) |url=http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250094603 |access-date= |website=efloras.org}}

Constance's bittercress is endemic to the Clearwater Mountain range in north-central Idaho. Populations have been found around the North and Middle Forks of the Clearwater River and throughout the Selway, Coeur d'Alene, and St. Joe River canyons in Clearwater, Idaho, Kootenai, Nez Perce, and Shoshone Counties in Idaho.{{Cite web |title=Cardamine constancei |url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.157986/Cardamine_constancei |access-date= |website=NatureServe Explorer}} It is most commonly found around the Selway River. The species is fairly abundant throughout its limited range, but is sensitive to human disturbance. The ability of the plant to spread and set seed is limited by soil moisture levels.Crawford, R.C. 1980. Ecological investigations and management implications of six northern Idaho endemic plants on the proposed endangered and threatened lists. Moscow, ID: University of Idaho. Thesis. 200 pp.

This species is most often found in moist, low-elevation ({{cvt|400|–|600|ft}}) mixed coniferous forests along rivers, specifically in the redcedar/maidenhair fern habitat type.Brunsfeld, Steven J., and Jack Sullivan. [https://www.webpages.uidaho.edu/~jacks/BrunsfeldSullivan.pdf "A multi-compartmented glacial refugium in the northern Rocky Mountains: evidence from the phylogeography of Cardamine constancei (Brassicaceae)."] Conservation Genetics 6 (2005): 895-904. It is tolerant of light disturbance and appears to favor shaded to partly open habitat, wooded creek bottoms, and hillsides.{{Cite web |title=Cardamine constancei |url=https://www.wildflower.org/plants/result.php?id_plant=CACO27 |access-date= |website=Lady Bird Johnson Wildflower Center - The University of Texas at Austin}} Flowering is rare and mainly occurs in plants in canopy openings; it will usually not flower in dense shade.

Contsance's bittercress only occurs in a known refugium for a number of rare, narrow-ranged endemics such as the Idaho giant salamander and nimapuna tigersnail. The canyons where the plant currently grows were not glaciated during the last Pleistocene ice age, and its range does not extend into canyons that were previously glaciated. Brunsfeld and Sullivan propose that the plant's current range is a relict population that became isolated in the canyons during the last ice age, and has subsequently not re-colonized its former range.

Constance's bittercress is threatened by human habitat modification, specifically mining, road building, logging, and decades of fire suppression. Its narrow range and specific habitat requirements have the potential to exacerbate the negative effects of human activities. As a result, the species is listed as vulnerable both at a federal and state level.

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constancei

Category:Flora of Idaho

Category:Plants described in 1935