Cirsium arizonicum var. arizonicum

Endemic
Synonyms: Cirsium arizonicum var. nidulum Cirsium nidulum
Treatment appears in FNA Volume 19. Treatment on page 143. Mentioned on page 142, 144, 145.

Stems glabrous to tomentose, usually without septate trichomes. Leaf-blades unlobed to deeply divided, faces usually ± tomentose, at least abaxially, usually without septate trichomes; main marginal spines 2–15 mm, often stout; cauline bases narrowed, truncate or clasping, but not or only slightly decurrent. Involucres cylindric to campanulate. Phyllary spines 1–20 mm, slender to very stout. Corollas usually bright red or pink, 24–34 mm, tubes 7–12, throats 2–5 mm, lobes 13–18 mm; style tips–2.5 mm. 2n = 30, 32, 34 (as C. arizonicum × C. nidulum).


Phenology: Flowering spring–fall (May–Oct).
Habitat: Pine-oak-juniper woodlands, montane coniferous forests, subalpine
Elevation: 1200–3600 m

Distribution

V19-125-distribution-map.gif

Ariz., Calif., Nev., N.Mex., Utah.

Discussion

Variety arizonicum is widely distributed across the uplands of the American Southwest from eastern California across the Basin and Range Province to the Colorado Plateau and the mountains of Arizona and New Mexico. It is the most widely distributed and most variable variety of Cirsium arizonicum. Viciously spiny plants with deeply divided leaves from the northern part of the range of var. arizonicum often have been treated as C. nidulum. These plants form a continuum with the less spiny plants of more southerly distribution, however, and separation of two varieties (or species) is arbitrary.

Leaves of some plants of var. arizonicum from Coconino County, Arizona, resemble those of the sympatric C. wheeleri. I have not seen hybrids between these taxa, but it is likely that some genetic interchange between the two has taken place in the past.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

34 +, 32 +  and 30 +
glabrous +  and densely gray tomentose +
glabrate +, glabrous +  and gray-tomentose +
short-tailed +
spineless +  and twisted +
spreading +  and ascending +
innermost +
inconspicuous +
scarious +
0.02 cm0.2 mm <br />2.0e-4 m <br /> (0.03 cm0.3 mm <br />3.0e-4 m <br />) +
paniculiform +  and corymbiform +
indeterminate +  and determinate +
David J. Keil +
(A. Gray) Petrak +
sessile +  and winged-petiolate +
decurrent +
Cnicus arizonicus +
compound +  and simple +
3 cm30 mm <br />0.03 m <br /> (40 cm400 mm <br />0.4 m <br />) +
spinulose;shallowly lobed or divided +
1cm;13cm +
with straight or flexuous spines +  and unarmed +
10-nerved or 20-nerved +  and rugose +
tawny +  and white +
clasping +  and truncate +
decurrent +  and narrowed +
actinomorphic +
pink +  and bright red +
2.4 cm24 mm <br />0.024 m <br /> (3.4 cm34 mm <br />0.034 m <br />) +
compressed +  and ovoid +
fertile +  and bisexual +
Ariz. +, Calif. +, Nev. +, N.Mex. +  and Utah. +
1200–3600 m +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Pine-oak-juniper woodlands, montane coniferous forests, subalpine +
indeterminate +
each +  and sessile +
1.5 cm15 mm <br />0.015 m <br /> (4 cm40 mm <br />0.04 m <br />) +
glabrous +  and arachnoid +
cylindric;campanulate +
1 cm10 mm <br />0.01 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
sessile +  and petiolate +
cauline +  and basal +
bristle-tipped +
divided +, lobed +, ovate +  and linear-acuminate +
0.2 cm2 mm <br />0.002 m <br /> (1.5 cm15 mm <br />0.015 m <br />) +
0.2 cm2 mm <br />0.002 m <br /> (3 cm30 mm <br />0.03 m <br />) +
usually lobed +  and dissected +
2-carpellate +
persistent +
1.7 cm17 mm <br />0.017 m <br /> (2.8 cm28 mm <br />0.028 m <br />) +
0 cm0 mm <br />0 m <br /> (15 cm150 mm <br />0.15 m <br />) +
Flowering spring–fall (May–Oct). +
middle +  and outer +
weakly to strongly +
slender to very +
0.1 cm1 mm <br />0.001 m <br /> (2 cm20 mm <br />0.02 m <br />) +
papillate +  and smooth +
Bot. Tidsskr. +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
glutinous +
inconspicuous +
tawny;white +
setiform +  and plumose +
exalbuminous +
subequal +
flexuous +  and straight +
erect +  and reflexed +
flattened +  and cylindric +
Slender (?) +  and Stout (?) +
0.1 cm1 mm <br />0.001 m <br /> (3 cm30 mm <br />0.03 m <br />) +
spiny-winged +, simple +  and branched +
ascending +  and erect +
1 +  and several +
appendaged +  and truncate +
dilated +  and swollen +
enlarged +
0.1 cm1 mm <br />0.001 m <br /> (0.4 cm4 mm <br />0.004 m <br />) +
Cirsium arizonicum var. nidulum +  and Cirsium nidulum +
Cirsium arizonicum var. arizonicum +
Cirsium arizonicum +
variety +
cylindric +
expanded +
0.2 cm2 mm <br />0.002 m <br /> (0.5 cm5 mm <br />0.005 m <br />) +
bristly-dentate to coarsely +
slender +
0.7 cm7 mm <br />0.007 m <br /> (1.25 cm12.5 mm <br />0.0125 m <br />) +
30 cm300 mm <br />0.3 m <br /> (150 cm1,500 mm <br />1.5 m <br />) +
tree +, vine +, shrub +  and subshrub +
0 cm0 mm <br />0 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +