Cirsium eatonii var. murdockii

S. L. Welsh

Great Basin Naturalist 42: 200. 1982

Common names: Northern mountain thistle
Synonyms: Cirsium murdockii (S. L. Welsh) Cronquist Cirsium polyphyllum (Rydberg) Petrak Cirsium tweedyi (Rydberg) Petrak
Treatment appears in FNA Volume 19. Treatment on page 152. Mentioned on page 126, 151, 156.
Click plate for higher resolution version.
Illustrator: John Myers
Stems erect or ascending, stout, 10–75 cm. Leaf faces glabrous or nearly so or abaxial ± villous and/or tomentose with septate or non-septate trichomes. Heads sessile or short-pedunculate in erect, few-headed, subcapitate or spiciform arrays. Involucres 2–3 cm, thinly to densely tomentose with septate or non-septate trichomes (phyllaries sometimes obscured by tomentum). Phyllaries green or purplish-tinged; outer with few lateral spines; apical spines slender. Corollas white to pink or lavender, 17–23 mm, tubes 6–10 mm, throats 5–8 mm, lobes 3–6 mm. Pappi 11–18 mm. 2n = 34 (as C. tweedyi).

Phenology: Flowering summer (Jul–Sep).
Habitat: Talus slopes, rocky subalpine and alpine ridges, openings in subalpine forests, subalpine meadows
Elevation: 2300–3900 m



Colo., Idaho, Mont., Nev., Utah, Wyo.


Of conservation concern.

Variety murdockii grows in the central Rocky Mountains from central Idaho and southern Montana to western Wyoming and northern Colorado. It also grows in the Ruby Mountains of northern Nevada and the Uintah Mountains of northeastern Utah. Considerable variation occurs in quantity and quality of pubescence of the involucres of </i>var.<i> murdockii. In some individuals the pubescence is so dense that it obscures the phyllary bodies whereas in others the individual phyllaries are clearly visible. Most commonly the pubescence consists primarily of septate trichomes, but sometimes finer non-septate trichomes predominate. Both types of trichomes may be present.

Variety murdockii is known to hybridize with Cirsium pulcherrimum var. pulcherrimum and C. scariosum var. scariosum in Wyoming.



Lower Taxa

No lower taxa listed.

AuthorDavid J. Keil +
AuthorityS. L. Welsh +
BasionymsCnicus eatonii +
Common nameNorthern mountain thistle +
DistributionColo. +, Idaho +, Mont. +, Nev. +, Utah + and Wyo. +
Elevation2300–3900 m +
HabitatTalus slopes, rocky subalpine and alpine ridges, openings in subalpine forests, subalpine meadows +
IllustratorJohn Myers +
PhenologyFlowering summer (Jul–Sep). +
Publication titleGreat Basin Naturalist +
Publication year1982 +
ReferenceNone +
Source xml grained fna xml/V19-20-21/V19 146.xml +
SynonymsCirsium murdockii +, Cirsium polyphyllum + and Cirsium tweedyi +
Taxon familyAsteraceae +
Taxon nameCirsium eatonii var. murdockii +
Taxon parentCirsium eatonii +
Taxon rankvariety +
VolumeVolume 19 +