{{Short description|Species of flowering plant}} {{Speciesbox |image =Cardamine micranthera or small anthered bittercress in the creek I 02.jpg |image_caption=In a stream in Patrick County, Virginia, USA |status = G2 |status_system = TNC |status_ref = <ref name=tnc>{{cite web|url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.145351/Cardamine_micranthera|title=''Cardamine micranthera''|website=NatureServe Network Biodiversity Location Data accessed through NatureServe Explorer|author=NatureServe|publisher=NatureServe|location=Arlington, Virginia|date=5 April 2024|access-date=14 April 2024}}</ref> |status2=LE |status2_system=ESA |status2_ref=<ref>{{cite web|url=https://ecos.fws.gov/ecp/species/3462|title=Small-anthered bittercress (''Cardamine micranthera'')|website=Environmental Conservation Online System|publisher=U.S. Fish & Wildlife Service|access-date=14 April 2024}}</ref><ref name=fed>{{cite journal|last1=Murdock|first1=Nora|author2=((U.S. Fish and Wildlife Service))|title=Endangered and Threatened Wildlife and Plants; Small Anthered Bittercress Determined To Be Endangered|journal=Federal Register|date=21 September 1989|volume=54|issue=182|pages=38947–38950}} {{Federal Register|54|38947}}</ref> |genus = Cardamine |species = micranthera |authority = Rollins }}
'''''Cardamine micranthera''''' is a rare species of flowering plant in the mustard family known by the common names '''small-anthered bittercress''' and '''streambank bittercress'''. It is endemic to the Piedmont region around the border between Virginia and North Carolina, and is today restricted to the Dan River watershed.<ref name=tnc/> It is in decline mainly because its habitat has been disturbed and destroyed by a number of processes.<ref name=tnc/> By the 1960s the only known populations of the plant had disappeared and in the 1970s it was feared extinct.<ref name=fed/><ref name=cpc>[http://www.centerforplantconservation.org/collection/cpc_viewprofile.asp?CPCNum=754 Center for Plant Conservation] {{webarchive |url=https://web.archive.org/web/20101215065833/http://www.centerforplantconservation.org/collection/cpc_viewprofile.asp?CPCNum=754 |date=December 15, 2010 }}</ref> The plant was rediscovered in the 1980s and for a while was presumed to be a rare North Carolina endemic; populations in Virginia have been confirmed since.<ref name=tnc/><ref name=fed/> The plant was federally listed as an endangered species in 1989 when it was known from only four tiny populations on unprotected private land.<ref name=fed/> Today there are about 32 occurrences; one occurrence in North Carolina has been extirpated and five others there had no specimens found at the most recent survey.<ref name=tnc/>
This is a perennial herb producing a slender, sometimes branching stem 20 to 40 centimeters tall. The leaves are alternately arranged and mostly simple, but the basal leaves may have small lobes. Each flower has four small white petals and stamens with tiny rounded anthers. The fruit is a silique around a centimeter long. The plant may be distinguished from its relative ''Cardamine rotundifolia'' by its smaller, rounder anthers, smaller petals, and shorter fruits.<ref name=tnc/><ref name=cpc/>
This plant occurs in moist and wet, shady areas near streams, on sand and gravel bars within the stream bed and in dim woodlands.<ref name=tnc/> It is an obligate wetland species.<ref>{{cite web|url=https://www.nrc.gov/docs/ML0428/ML042800168.pdf|title=1996 National List of Vascular Plant Species That Occur in Wetlands|date=January 24, 1997|publisher=Ecology Section, National Wetlands Inventory, U.S. Fish and Wildlife Service|access-date=14 April 2024|via=United States Nuclear Regulatory Commission}}</ref>{{rp|34}} This habitat around the North Carolina–Virginia border has been impacted by human activity such as conversion to pasture, agricultural fields, and residential property.<ref name=tnc/> The land is also affected by surface runoff and herbicide drift from nearby agricultural operations, and trampling by livestock may occur.<ref name=tnc/> Invasive plant species such as Japanese honeysuckle (''Lonicera japonica'') and Japanese stiltgrass (''Microstegium vimineum'') now occur in the area.<ref name=tnc/> Flooding<ref name=tnc/><ref name=cpc/> and logging<ref name=cpc/> have been listed as threats, as well.
==References== {{Reflist}}
==External links== *[https://plants.usda.gov/java/profile?symbol=CAMI19 USDA Plants Profile]
{{Taxonbar|from=Q5038232}}
micranthera Category:Flora of North Carolina Category:Flora of Virginia