View source for Cirsium clavatum var. americanum

{{Treatment/ID
|accepted_name=Cirsium clavatum var. americanum
|accepted_authority=(A. Gray) D. J. Keil
|publications={{Treatment/Publication
|title=Sida
|place=21: 211. 2004
|year=2004
}}
|common_names=Rocky Mountain fringed thistle
|special_status={{Treatment/ID/Special_status
|code=E
|label=Endemic
}}
|basionyms={{Treatment/ID/Basionym
|name=Cnicus carlinoides var. americanus
|authority=A. Gray
|rank=variety
|publication_title=Proc. Amer. Acad. Arts
|publication_place=10: 48. 1874
}}
|synonyms={{Treatment/ID/Synonym
|name=Cirsium centaureae
|authority=(Rydberg) K. Schumann
|rank=species
}} {{Treatment/ID/Synonym
|name=Cirsium griseum
|authority=(Rydberg) K. Schumann
|rank=species
}} {{Treatment/ID/Synonym
|name=Cirsium laterifolium
|authority=(Osterhout) Petrak
|rank=species
}} {{Treatment/ID/Synonym
|name=Cirsium modestum
|authority=(Osterhout) Cockerell
|rank=species
}} {{Treatment/ID/Synonym
|name=Cirsium scapanolepis
|authority=Petrak
|rank=species
}} {{Treatment/ID/Synonym
|name=Cirsium spathulifolium
|authority=Rydberg
|rank=species
}}
|hierarchy=Asteraceae;Asteraceae tribe Cardueae;Cirsium;Cirsium clavatum;Cirsium clavatum var. americanum
|hierarchy_nav=<div class="higher-taxa"><div class="higher-taxon"><small>family</small>[[Asteraceae]]</div><div class="higher-taxon"><small>tribe</small>[[Asteraceae tribe Cardueae]]</div><div class="higher-taxon"><small>genus</small>[[Cirsium]]</div><div class="higher-taxon"><small>species</small>[[Cirsium clavatum]]</div><div class="higher-taxon"><small>variety</small>[[Cirsium clavatum var. americanum]]</div></div>
|volume=Volume 19
|mention_page=page 126, 127
|treatment_page=page 128
}}<!--

--><span class="statement" id="st-undefined" data-properties=""><b>Abaxial </b>leaf faces ± tomentose. <b>Involucres</b> ovoid to campanulate, 1.5–3 × 1.5–3 cm, glabrous or thinly arachnoid-tomentose with fine, non-septate trichomes. <b>Phyllaries</b> in 5–6 series, strongly imbricate to subequal, green or with maroon to dark brown subapical patch or appendage, linear to ovate, abaxial faces with narrow glutinous ridge; outer and middle bases appressed, apical appendages erect or ascending, linear-lanceolate to obovate, entire or more commonly dilated, scarious, and erose-toothed to fringed, acicular-acuminate to broadly obtuse, spines erect or ascending, 1–6 mm, often flattened; apices of inner sometimes flexuous or reflexed, narrow, flat, and entire or more commonly ± expanded, scarious, and lacerate-dentate. <b>2n</b> = 34, 36 (as C. centaureae).</span><!--

-->{{Treatment/Body
|phenology=Flowering summer (Jun–Sep).
|habitat=Oak scrub, sagebrush scrub, grasslands, juniper-pine woodlands, aspen groves, openings in montane coniferous forests
|elevation=2100–3100 m
|distribution=Colo.;Utah;Wyo.
|discussion=<p>Variety americanum is scattered in the Rocky Mountains of south-central Wyoming and Colorado. The varietal epithet americanum was based upon syntypes from both Colorado and California. The latter are referable to <i>Cirsium remotifolium</i>.</p><!--
--><p>Variations in leaf characteristics, head size, and phyllary features combined with a narrow species concept led Osterhout and Rydberg to propose several species and hybrids for what I am treating as one taxon. Variety americanum certainly is polymorphic and in need of further study focused on local and regional variation. It is possible that some of the local variants in Colorado may deserve taxonomic recognition, but I have been unable to detect consistent patterns in the variation. Some specimens from Route and Jackson counties there closely approach <i></i>var.<i> clavatum</i>. Others from southeastern Wyoming approach <i>Cirsium pulcherrimum </i>var.<i> pulcherrimum</i> and may be hybrids or derivatives of past hybridization.</p>
|tables=
|references=
}}<!--

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-->{{#Taxon:
name=Cirsium clavatum var. americanum
|authority=(A. Gray) D. J. Keil
|rank=variety
|parent rank=species
|synonyms=Cirsium centaureae;Cirsium griseum;Cirsium laterifolium;Cirsium modestum;Cirsium scapanolepis;Cirsium spathulifolium
|basionyms=Cnicus carlinoides var. americanus
|family=Asteraceae
|phenology=Flowering summer (Jun–Sep).
|habitat=Oak scrub, sagebrush scrub, grasslands, juniper-pine woodlands, aspen groves, openings in montane coniferous forests
|elevation=2100–3100 m
|distribution=Colo.;Utah;Wyo.
|reference=None
|publication title=Sida
|publication year=2004
|special status=Endemic
|source xml=https://bitbucket.org/aafc-mbb/fna-data-curation/src/2e0870ddd59836b60bcf96646a41e87ea5a5943a/coarse_grained_fna_xml/V19-20-21/V19_92.xml
|tribe=Asteraceae tribe Cardueae
|genus=Cirsium
|species=Cirsium clavatum
|variety=Cirsium clavatum var. americanum
}}<!--

-->[[Category:Treatment]][[Category:Cirsium clavatum]]