Cirsium arizonicum
{{Short description|Species of thistle}}
{{Speciesbox
|image = Red Thistle 1.JPG
|status = {{TNCStatus}}
|status_system = TNC
|genus = Cirsium
|species = arizonicum
|synonyms_ref = [http://www.theplantlist.org/tpl1.1/record/gcc-123754 The Plant List, Cirsium arizonicum (A.Gray) Petr. ]
|synonyms = {{collapsible list|bullets = true
|title=Synonymy
|Carduus arizonicus (A.Gray) Greene
|Carduus nidulus (M.E.Jones) A.Heller
|Cirsium nidulum (M.E.Jones) Petr.
|Cnicus arizonicus A.Gray
|Cnicus nidulus M.E.Jones
|Cirsium effusum (Maxim.) Matsum.
|Cnicus effusus Maxim.
|Cirsium chellyense R.J.Moore & Frankton
|Cirsium chuskaense R.J.Moore & Frankton
|Cirsium navajoense R.J.Moore & Frankton
|Carduus rothrockii (A.Gray) Greene
|Cirsium rothrockii (A.Gray) Petr.
|Cnicus rothrockii A.Gray
|}}}}
Cirsium arizonicum, the Arizona thistle, is a North American species of thistle in the family Asteraceae, native to the southwestern United States and northwestern Mexico. It has been found in Arizona, southeastern California, New Mexico, Nevada, Colorado, Utah, Sonora, and northwestern Chihuahua.Flora of North America: [http://www.efloras.org/florataxon.aspx?flora_id=1&taxon_id=250066358 Cirsium arizonicum]Jepson Flora: [http://ucjeps.berkeley.edu/cgi-bin/get_JM_treatment.pl?Cirsium+arizonicum Cirsium arizonicum]USDA Plants Profile: [http://plants.usda.gov/java/profile?symbol=CIAR3 Cirsium arizonicum][http://bonap.net/MapGallery/County/Cirsium%20arizonicum.png Biota of North America Program 2014 county distribution map][http://www.calflora.org/cgi-bin/species_query.cgi?where-calrecnum=2117 Calflora taxon report, University of Arizona, Cirsium arizonicum (A. Gray) Petrak Arizona thistle ]
Cirsium arizonicum is a herbaceous plant that can be either biennial or perennial, reaching 30–150 cm in height. The spiny leaves are oblong-obovate with pinate lobes; the basal leaves are larger, 10–40 cm long, while leaves on the upper stem can be only 3 cm long. The inflorescence is 3–4 cm in length and 1.5–2 cm diameter, red to pink or purple, with all the florets of similar form (no division into disc and ray florets); individual plants are very variable in the number of heads produced, from one to 100. Flowering is from mid spring to mid fall. The species occurs in mountains, at elevations of 900–3,600 m.[http://swbiodiversity.org/seinet/taxa/index.php?taxon=38 SEINet Southwestern Biodiversity, Arizona Chapter, Cirsium arizonicum] includes photos, description, distribution map
Five varieties have been identified:
- Cirsium arizonicum var. arizonicum (syn. var. nidulum (M.E.Jones) S.L.Welsh) – Arizona, New Mexico, California, Nevada, Utah, Sonora, Chihuahua
- Cirsium arizonicum var. bipinnatum (Eastwood) D.J.Keil. Four Corners thistle – Arizona, New Mexico, Colorado, Utah, Sonora
- Cirsium arizonicum var. chellyense (R.J.Moore & Frankton) D.J.Keil (syn. C. chellyense R.J.Moore & Frankton) Navajo thistle – Arizona, New Mexico
- Cirsium arizonicum var. rothrockii (A.Gray) D.J.Keil (syn. C. rothrockii (A.Gray) Petrak). Rothrock's thistle – Arizona, New Mexico, Sonora; this variety is found on both rims of the Grand Canyon and for a short distance below.{{Cite book|title=Grand Canyon Wildflowers|last=Phillips, III|first=Arthur|publisher=Grand Canyon Natural History Association|year=1979}}
- Cirsium arizonicum var. tenuisectum D.J.Keil. Desert mountains thistle – California, Nevada, Sonora
References
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Category:Flora of the Southwestern United States