Cirsium eatonii var. viperinum

D. J. Keil

Sida 21: 212. 2004.

Common names: Snake Range thistle
Treatment appears in FNA Volume 19. Treatment on page 151. Mentioned on page 135.

Stems erect or ascending, 25–40 cm. Leaf faces glabrous or nearly so. Heads 1–5, subsessile or short-pedunculate, in erect, racemiform or corymbiform arrays. Involucres 3–5 cm, thinly arachnoid with non-septate trichomes, individual phyllaries evident. Phyllaries green or purplish-tinged; outer with numerous lateral spines; apical spines stout. Corollas lavender to purple, 29–35 mm, tubes 9–12.5 mm, throats 9–12 mm, lobes 9–11 mm. Pappi 20–25 mm.


Phenology: Flowering summer (Jul–Sep).
Habitat: Rocky subalpine slopes, open bristlecone pine forests
Elevation: 3300–3500 m

Discussion

Variety viperinum is apparently endemic to upper elevations of the Snake Range of White Pine County, Nevada. Heads of var. viperinum are similar in size to those of var. clokeyi. These taxa can be distinguished readily by the features in the key. Ranges of the two varieties are separated by about 340 km. Hybridization with Cirsium inamoenum is suspected based upon apparently intermediate specimens.

Selected References

None.

Lower Taxa

None.

"fine" is not a number.

villous +  and glabrous +
villous +, glabrous +  and arachnoid-tomentose +
short-tailed +
spineless +  and twisted +
dentate +, entire +  and spine-tipped +
usually stiffly ascending +  and spreading +
innermost +
scarious +
not differentiated +
corymbiform +  and racemiform +
indeterminate +  and determinate +
David J. Keil +
D. J. Keil +
sessile +, winged-petiolate +  and spiny +
decurrent +
Cnicus eatonii +
compound +  and simple +
10 cm100 mm <br />0.1 m <br /> (30 cm300 mm <br />0.3 m <br />) +
1cm;5cm +
10-nerved or 20-nerved +  and rugose +
spiny-fringed +
tawny +  and white +
? (?) +  and ? (?) +
Snake Range thistle +
actinomorphic +
lavender +  and purple +
2.9 cm29 mm <br />0.029 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
compressed +  and ovoid +
fertile +  and bisexual +
3300–3500 m +
gray-canescent +  and glabrous +
pistillate +, staminate +  and neuter +
winged +  and beaked +
dispersed +
Rocky subalpine slopes, open bristlecone pine forests +
short-pedunculate +  and subsessile +
indeterminate +
nodding +  and erect +
each +  and sessile +
suffused with dark purple +  and green +
2 cm20 mm <br />0.02 m <br /> (5 cm50 mm <br />0.05 m <br />) +
broadly ovoid;campanulate +
3 cm30 mm <br />0.03 m <br /> (5 cm50 mm <br />0.05 m <br />) +
1.5 cm15 mm <br />0.015 m <br /> (5 cm50 mm <br />0.05 m <br />) +
sessile +  and petiolate +
nearly +  and glabrous +
cauline +  and basal +
bristle-tipped +
deltate +, usually narrowly triangular +  and more or less linear +
0.2 cm2 mm <br />0.002 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
3-lobed +, lance-oblong +  and broadly triangular +
2-carpellate +
persistent +
2 cm20 mm <br />0.02 m <br /> (2.5 cm25 mm <br />0.025 m <br />) +
0 cm0 mm <br />0 m <br /> (14 cm140 mm <br />0.14 m <br />) +
Flowering summer (Jul–Sep). +
spine-tipped +  and plane +
middle +  and outer +
papillate +  and smooth +
sessile +  and winged-petiolate +
bearing subulate enations +, hairy +  and bristly +
flat;convex +
glutinous +
tawny;white +
setiform +  and plumose +
exalbuminous +
subequal +
Illustrated +  and Endemic +
0.7 cm7 mm <br />0.007 m <br /> (3.5 cm35 mm <br />0.035 m <br />) +
branched +, simple +  and sparingly branched +
ascending +  and erect +
1 +  and several +
25 cm250 mm <br />0.25 m <br /> (40 cm400 mm <br />0.4 m <br />) +
appendaged +  and truncate +
dilated +  and swollen +
enlarged +
0.3 cm3 mm <br />0.003 m <br /> (0.6 cm6 mm <br />0.006 m <br />) +
Compositae +
Cirsium eatonii var. viperinum +
Cirsium eatonii +
variety +
cylindric +
expanded +
0.9 cm9 mm <br />0.009 m <br /> (1.2 cm12 mm <br />0.012 m <br />) +
bristly-dentate to coarsely +
arachnoid-tomentose +
slender +
0.9 cm9 mm <br />0.009 m <br /> (1.25 cm12.5 mm <br />0.0125 m <br />) +
10 cm100 mm <br />0.1 m <br /> (150 cm1,500 mm <br />1.5 m <br />) +
tree +, vine +, shrub +  and subshrub +