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Cirsium occidentale var. coulteri

Higher Taxonomy
Family: Asteraceae (Compositae)View DescriptionDichotomous Key

eFlora Treatment Author: David J. Keil, except as noted
Genus: CirsiumView DescriptionDichotomous Key

Common Name: THISTLE
Habit: Taprooted annual, biennial, or short-lived perennial herb that flowers once, or multi-flower perennial herb with taprooted rosettes arising from runner roots or from simple to branched caudex; glabrous to cobwebby or +- densely tomentose with long, fine, slender hairs, sometimes with thicker multicellular, jointed hairs that often appear crinkled, shining, iridescent when dry. Stem: generally erect. Leaf: basal and proximal cauline generally tapered or +- wing-petioled, generally wavy-margined, dentate to generally pinnately lobed and +- dentate, lobes and teeth spine-tipped, generally spiny-ciliate, faces glabrous to tomentose, especially abaxially; distal generally sessile, +- reduced. Inflorescence: heads discoid, 1--many, center head of cluster generally larger, generally erect; involucre +- cylindric to ovoid, spheric, or bell-shaped, persistent when dry; phyllaries many, graduated in 5--20 series, generally entire (spiny-ciliate or with irregularly toothed or cut scarious margin or distal appendage), outer and middle generally spine-tipped, in some species midrib with sticky-resinous ridge (milky when fresh, dark when dry, occasionally very narrow); inner phyllaries generally narrow, flat, tips straight or twisted; receptacle flat, long-bristly, epaleate. Flower: +- many, generally bisexual (unisexual in Cirsium arvense); corolla +- radial, white to red or purple, tube long, narrowly cylindric, throat cylindric, lobes linear; anther tube colored same as corolla or not, anther base sharply sagittate, tip linear or oblong; style generally exserted, tip cylindric, branches very short. Fruit: ovoid, thick or +- compressed, straw-colored or tan to dark brown, glabrous; attachment scar slightly angled; pappus bristles many, +- flattened proximally, plumose, weakly fused at base, often deciduous in ring, white to brown.
Species In Genus: +- 200 species: North America, Eurasia. Etymology: (Greek: thistle) Note: Taxa difficult, variable, incompletely differentiated, hybridize. Exceptional white-flowered plants occur in most taxa with pigmented corollas; these generally not treated in key.
Unabridged Note: Native thistles are part of an apparently actively evolving group of species with many geog and ecological races and growth forms. Morphologically divergent species often are able to hybridize; unrecognized hybridization or intergradation often complicates identification. Stature, growth form, and proportions are subject to environmental influence.
Species: Cirsium occidentaleView Description 

Habit: Biennial 0.3--30 dm. Stem: generally 1, generally erect, branched distally (stem +- 0 or branched +- throughout in dwarf plants), +- tomentose. Leaf: +- densely gray- or +- white-tomentose, especially abaxially, occasionally +- glabrous in age; proximal 1--4 dm, petiole spiny-winged, blade oblanceolate, lobed 1/2+ to midvein, lobes widely triangular, dentate or further lobed, main spines 1--10 mm; distal gradually reduced, +- clasping or short-decurrent, linear or oblong, often entire, often spinier than proximal, distal-most often bract-like. Inflorescence: heads 1--several in loose to tight cluster (barely raised above rosette in dwarf plants); peduncle 1--30 cm; involucre 1.5--5 cm, 1.5--8 cm diam, ovoid to spheric or wider; phyllaries +- equal to strongly graduated, needle-like to lance-linear, straight or twisted or bent, appressed to widely radiating, +- glabrous to densely tomentose, sometimes connected side-to-side by network of conspicuous cobwebby hairs, tip-spine 1--10+ mm. Flower: corolla 18--35 mm, white to lavender, purple, or red, tube 8--18 mm, throat 5--7 mm, lobes 5--10 mm; style tip 4--5 mm. Fruit: 5--6 mm; pappus 15--30 mm.
Note: Variable complex; some plants may not be assignable to var. Needs study. Related to Cirsium neomexicanum.

Cirsium occidentale var. coulteri (Harv. & A. Gray) Jeps.
Habit: Plants generally 3--15+ dm, erect or bushy, variably tomentose, occasionally +- glabrous. Inflorescence: heads generally long-peduncled, occasionally in tight clusters at peduncle ends; involucre generally +- as wide as high, 4--5 cm diam, densely cobwebby; phyllaries without sticky-resinous ridge, needle-like, 13--30 mm, outer generally +- = middle and inner, ascending to stiffly spreading. Flower: corolla generally 25--33 mm, light purple to rich red-purple.
Ecology: Grassland, dunes, oak woodland, scrub; Elevation: generally < 700 m. Bioregional Distribution: CCo, SCo, ChI. Flowering Time: Mar--Jun Note: Occasionally intergrades with Cirsium occidentale var. occidentale; some ChI plants approach Cirsium occidentale var. compactum.
Synonyms: Cirsium coulteri Harv. & A. Gray
eFlora Treatment Author: David J. Keil
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Citation for this treatment: David J. Keil 2016. Cirsium occidentale var. coulteri, in Jepson Flora Project (eds.) Jepson eFlora, http://ucjeps.berkeley.edu/cgi-bin/get_IJM.pl?tid=81843, accessed on August 28, 2016.

Citation for the whole project: Jepson Flora Project (eds.) 2016. Jepson eFlora, http://ucjeps.berkeley.edu/IJM.html, accessed on August 28, 2016.

Geographic subdivisions for Cirsium occidentale var. coulteri:
CCo, SCo, ChI.
map of distribution 1

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Data provided by the participants of the Consortium of California Herbaria.
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CCH collections by month

Duplicates counted once; synonyms included.
Species do not include records of infraspecific taxa.
Blue line denotes eFlora flowering time.