View source for Cirsium arizonicum

{{Plant2000
|apex external texture=ciliolate
|apex height or length=short
|apex length=inconspicuous
|apex orientation=spreading;ascending
|apex prominence or shape=flat
|apex shape=entire
|apex width=narrow
|array architecture=corymbiform;paniculiform
|base architecture=clasping
|base architecture or shape=bractlike
|base position=distalmost
|base shape=decurrent
|blade arrangement or shape=oblong-elliptic
|blade shape=unlobed;spinulose;lobed;divided
|body height or length=short
|body orientation=appressed
|body position=outer
|body shape=entire
|branch orientation=ascending
|caudex architecture=taprooted
|chromosome count=30;32;34
|collar coloration=stramineous
|corolla coloration=pink;red;lavender;purple;white
|cypsela coloration=brown
|face architecture=sessile
|face arrangement=distributed
|face coloration=green;green
|face count=present
|face external texture=glabrous;gray;villous;glabrous;gray-tomentose;glabrate
|face other=principal
|face position=adaxial;basal;cauline
|face size=diminished
|head orientation=erect
|involucre external texture=arachnoid;glabrous
|involucre shape=cylindric;ovoid;campanulate
|lobe shape=ovate;linear-acuminate;lobed;divided
|phyllary arrangement=imbricate
|phyllary coloration=green;inner reddish to rich reddish-c-purple;inner;rich
|phyllary shape=ovate;lanceolate;linear
|ridge prominence=inconspicuous
|ridge width=narrow
|spine architecture=unarmed
|spine course=straight;flexuous
|spine fragility=stout
|spine orientation=erect;reflexed;ascending
|spine position=inner
|spine shape=cylindric;flattened
|spine size=slender
|stem external texture=glabrous;arachnoid-tomentose;glabrate
|stem orientation=erect;ascending
|trichome architecture=non-septate;septate;septate
|trichome external texture=villous
|trichome width=fine
|whole organism life style=perennial
|wing architecture or shape=spiny
}}
The Cirsium arizonicum complex is widely distributed from the Sierra Nevada, White Mountains, and New York Mountains of eastern California across the mountains of the southern Great Basin and Colorado Plateau to the mountains of eastern Colorado, Arizona, and New Mexico. This group of plants comprises a series of intergrading races with intricately overlapping patterns of variation. For plants that I am treating as C. arizonicum (in the broad sense), F. Petrak (1917) recognized three species, one with a variety and two subspecies plus his unstated type subspecies and variety. R. J. Moore and C. Frankton (1974b) revised the complex, recognizing six species, three of them newly described, for the plants I treat as C. arizonicum plus C. turneri, which I do not include in C. arizonicum. P. L. Barlow-Irick (2002), in a work focused on statistical analyses of variation patterns, recognized six species also, but circumscribed very differently from those of Moore and Frankton. Two of the species proposed by Barlow-Irick have not been formally described.
apex external texture	ciliolate +
apex height or length	short +
apex length	inconspicuous +
apex orientation	spreading + and ascending +
apex prominence or shape	flat +
apex shape	entire +
apex width	narrow +
array architecture	corymbiform + and paniculiform +
base architecture	clasping +
base architecture or shape	bractlike +
base position	distalmost +
base shape	decurrent +
blade arrangement or shape	oblong-elliptic +
blade shape	unlobed +, spinulose +, lobed + and divided +
body height or length	short +
body orientation	appressed +
body position	outer +
body shape	entire +
branch orientation	ascending +
caudex architecture	taprooted +
chromosome count	30 +, 32 + and 34 +
collar coloration	stramineous +
corolla coloration	pink +, red +, lavender +, purple + and white +
cypsela coloration	brown +
face architecture	sessile +
face arrangement	distributed +
face coloration	green +
face count	present +
face external texture	glabrous +, gray +, villous +, gray-tomentose + and glabrate +
face other	principal +
face position	adaxial +, basal + and cauline +
face size	diminished +
head orientation	erect +
involucre external texture	arachnoid + and glabrous +
involucre shape	cylindric +, ovoid + and campanulate +
lobe shape	ovate +, linear-acuminate +, lobed + and divided +
phyllary arrangement	imbricate +
phyllary coloration	green +, inner reddish to rich reddish-c-purple +, inner + and rich +
phyllary shape	ovate +, lanceolate + and linear +
ridge prominence	inconspicuous +
ridge width	narrow +
spine architecture	unarmed +
spine course	straight + and flexuous +
spine fragility	stout +
spine orientation	erect +, reflexed + and ascending +
spine position	inner +
spine shape	cylindric + and flattened +
spine size	slender +
stem external texture	glabrous +, arachnoid-tomentose + and glabrate +
stem orientation	erect + and ascending +
trichome architecture	non-septate + and septate +
trichome external texture	villous +
trichome width	fine +
whole organism life style	perennial +
wing architecture or shape	spiny +