View source for Streptanthus glandulosus subsp. niger

{{Short description|Species of herb}}
{{Infraspeciesbox
|image = Streptanthus niger.jpg
|image_caption =  Tiburon jewelflower
|status = LE
|status_system = ESA
|genus = Streptanthus
|species = glandulosus
|subspecies = niger
|authority = ([[Edward Lee Greene|Greene]]) Al-Shehbaz, M.S.Mayer & D.W.Taylor (2008)
|synonyms =
*''Euklisia nigra'' {{small|(Greene) Greene (1904)}}
*''Streptanthus glandulosus'' var. ''niger'' {{small|(Greene) Munz (1958)}}
*''Streptanthus niger'' {{small|Greene (1886)}}
|synonyms_ref = <ref name = powo>[https://powo.science.kew.org/taxon/urn:lsid:ipni.org:names:60448935-2 ''Streptanthus glandulosus'' subsp. ''niger'']. ''[[Plants of the World Online]]''. Retrieved 13 December 2023.</ref>
}}
'''''Streptanthus glandulosus'' subsp. ''niger''''' is an [[endangered species|endangered]] subspecies of [[flowering plant]] within the family [[Brassicaceae]].<ref name = powo/> Like other genus members, this [[herbaceous plant|herb]] has wavy [[petal]] margins with perimeter [[callus (cell biology)|callus]]es that discourage [[larva]]l [[herbivore|herbivory]].<ref>Kruckeberg & Morrison 1983 Madroño 30:230–244</ref> This plant is [[endemic (ecology)|endemic]] to the [[Tiburon, California|Tiburon Peninsula]]<ref>''Marinero Estates Environmental Impact Report, Tiburon, California'', Earth Metrics Inc., prepared for the city of Tiburon, Ca (1989)</ref> of [[Northern California]], and occurs at elevations below 150 m on [[serpentine soils|serpentine]] [[grassland]]s.<ref>''[[Willis Linn Jepson|Jepson]] Manual'', [[University of California]] Press (1993)</ref> The common name for this subspecies is '''Tiburon jewelflower'''<ref>{{PLANTS|id=STNI2|taxon=Streptanthus niger|accessdate=4 December 2015}}</ref> or '''black jewelflower'''. This annual herb blooms in May and June and displays dark purple [[sepal]]s. The [[etymology]] of this genus scientific name derives from the [[Ancient Greek|Greek]] word ''streptanthus'', meaning ''twisted flower'', with reference to the notable wavy margins of the petals. The subspecies name ''niger'' relates to the color of the [[seed]]s being black, although an alternate account cites the dark color of the petals as the source of the appellation.
==Description==
''Streptanthus glandulosus'' subsp. ''niger'' is an [[Annual plant|annual]] [[Herbaceous|herb]] attaining a height of 20 to 70 centimeters. The plant architecture may manifest as simple-stemmed or branching in the upper part. Lower portions of the stems are smooth and practically hairless. This [[self-pollination|self-pollinated]] plant has dark purple, almost black, flower petals; moreover, the [[petals]] have a purple claw and a white blade with a purple midvein. The zig-zag [[inflorescence]] pattern is an identifying characteristic; furthermore, the flower is almost closed at its throat. [[Sepals]] measure five to seven mm. The characteristic wavy petal margins have calluses that inhibit larval [[herbivory]]. The leaves of ''S. g. niger'' appear in a [[anatomical terms of location|basal]] manifestation and measure less than nine centimeters in length; leaves are generally oblanceolate in shape, and may appear as coarsely [[Leaf#Margins (edge)|dentate]] or short-lobed. [[Chromosome|Chromosomal]] characterization is 2n=28. This plant is also known for belonging to the mustard family and producing black mustard seeds.
==Taxonomy==
This is a subspecies of the [[Streptanthus glandulosus|bristly jewelflower]] (''Streptanthus glandulosus'').<ref>[http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250095221 Flora of North America: ssp. ''niger'']</ref>
==Distribution and habitat==
There are only two known colonies of Tiburon jewelflower, both of which occur on the Tiburon Peninsula, with a separation of about three km. One of the populations is in the vicinity of the historic [[Old Saint Hilary's Church]]. The Federal Register listing document noted that ''S. niger'' occurs only on [[grassland]]s above shallow [[serpentine soil]]s involving gentle to moderate southwestern facing slopes. The listing statement further notes that: "Serpentine soils are derived from [[ultramafic]] rocks such as [[serpentinite]], [[dunite]], and [[peridotite]], which are found in discontinuous [[outcrop]]s in the...[[California Coast Ranges|Coast Ranges]]".<ref>[[Federal Register]]: February 3, 1995 (Volume 60, Number 23) [Page 6671-6685]</ref> According to the Sacramento Fish and Wildlife Service: "species such as Tiburon jewelflower have adapted to serpentine soils and require them to survive".<ref>[http://www.fws.gov/sacramento/es/plant_spp_accts/tiburon_jewelflower.htm Sacramento Fish and Wildlife Office profile for  ''Streptanthus niger'']</ref>
==Conservation==
The Tiburon jewelflower was first collected by Edward L. Greene in 1886 at the site of Old Saint Hilary's Church on the Tiburon Peninsula. ''Streptanthus niger'' was designated as endangered by the state of California in the year 1990 and listed by the U.S. federal government five years later. By 1998 a ''Species Recovery Plan'' had been prepared to provide more specific protection measures for this endangered [[dicotyledon]].<ref>''Recovery Plan for Serpentine Soil Species of the San Francisco Bay Area'' [[U.S. Fish and Wildlife Service]] (1998)</ref> For each of the two known colonies, the population has varied between 25 and 2000 over recent years, indicating the precariousness of the species. An assistant professor from [[Mills College]], with financial support from the Marin Country Open Space District, is carrying out a three year research project on conservation of the species.<ref>{{cite news | last =Rodriguez | first =Adrian | title =Endangered Tiburon jewelflower finds home on Ring Mountain| newspaper =[[Marin Independent Journal]] | date =July 19, 2018 | url =http://www.marinij.com/environment-and-nature/20161111/endangered-tiburon-jewelflower-finds-home-on-ring-mountain| accessdate =September 1, 2019 }}</ref> The [[California Native Plant Society]] has placed ''S. niger'' on List 1B (rare or endangered throughout its range).
==References==
{{Reflist}}
==External links==
*[https://ucjeps.berkeley.edu/eflora/eflora_display.php?tid=88851 ''Streptanthus glandulosus'' subsp. ''niger'', Tiburon Jewelflower] [[Jepson Manual]] treatment
{{Taxonbar|from1=Q24688463|from2=Q7623326}}
[[Category:Streptanthus|glandulosus niger]]
[[Category:Endemic flora of California]]
[[Category:Natural history of Marin County, California]]
[[Category:Tiburon, California]]
[[Category:Endemic flora of the San Francisco Bay Area]]
[[Category:Environment of the San Francisco Bay Area]]
[[Category:Plants described in 1886]]