Flora of North America species comparison

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Cirsium eatonii var. peckii

Cirsium eatonii var. hesperium
Cirsium eatonii var. peckii

Peck's thistle, Steens Mountain or ghost thistle, Steens Mountain thistle
Photo is of parent taxon

tall mountain thistle
Stems

erect or ascending, stout, 10–150 cm.

strictly erect, 50–150 cm.
Leaf

faces glabrous or nearly so or abaxial ± villous with septate trichomes.

faces glabrous or nearly so or abaxially finely arachnoid-tomentose and/or villous to tomentose with septate trichomes on one or both faces.
Involucres

2–4 cm, loosely to densely villous with septate trichomes and thinly arachnoid with non-septate trichomes.

2–2.5 cm, tomentose with septate trichomes;

outer phyllaries with a few stiff lateral spines;

spines of phyllaries slender.
Corollas

pink to purple, 21–25 mm, tubes 6.5–8 mm, throats 8–11.5 mm, lobes 5.5–7 mm.

pink or pale to deep purple, 14–21 mm, tubes 4.5–10 mm, throats 3.5–5 mm, lobes 3.5–7 mm.
Phyllaries

green;

outer with few or no lateral spines;

apical spines stout.

Heads

several–many, usually subsessile or short-pedunculate, crowded in erect, spiciform or racemiform arrays, less commonly openly branched.

usually sessile in stiffly erect, tight spiciform arrays, sometimes also sessile in distal leaf axils.
Pappi

17–22 mm.

8–17 mm.
2n

= 34 (as C. peckii).

Cirsium eatonii var. peckii

Cirsium eatonii var. hesperium
Phenology Flowering summer (Jun–Aug). Flowering summer (Jul–Sep).
Habitat Grasslands, juniper woodlands, grass-sagebrush steppes, subalpine slopes, roadsides Rocky slopes, subalpine meadows, forest openings
Elevation 1300–2900 m [4300–9500 ft] 2700–3400 m [8900–11200 ft]
Distribution
from FNA
NV; OR
[BONAP county map]
from FNA
CO
Discussion

Variety peckii occurs from Steens Mountain and the Pueblo Mountains of Harney County, Oregon, south to the Black Rock Range and Jackson Mountains of Humboldt County, Nevada. On the lower portion of its distribution along Steens Mountain Loop Road at an elevation of about 1900 m, var. peckii and Cirsium inamoenum grow together and freely hybridize, forming a complex hybrid swarm. Intermediates variably combine the features of the parent taxa, with the habit more openly branched than typical for C. eatonii var. peckii, variably arachnoid tomentose leaves, ± glandular phyllaries, and lavender to pale pink flowers. Variety peckii may range as far south as the West Humboldt Mountains. The type of Cirsium humboldtense Rydberg (Carduus nevadensis Greene) closely resembles some of the hybrids between C. inamoenum and C. eatonii var. peckii.

(Discussion copyrighted by Flora of North America; reprinted with permission.)

Variety hesperium is distributed in the San Juan Mountains and Spanish Peaks area of southern Colorado. It differs from var. eriocephalum in its stiffly erect arrays. Plants from the Spanish Peaks area approach var. eriocephalum.

(Discussion copyrighted by Flora of North America; reprinted with permission.)
Source FNA vol. 19, p. 153. Treatment author: David J. Keil. FNA vol. 19, p. 152. Treatment author: David J. Keil.
Parent taxa Asteraceae > tribe Cardueae > Cirsium > Cirsium eatonii Asteraceae > tribe Cardueae > Cirsium > Cirsium eatonii
Sibling taxa
C. eatonii var. clokeyi, C. eatonii var. eatonii, C. eatonii var. eriocephalum, C. eatonii var. hesperium, C. eatonii var. murdockii, C. eatonii var. viperinum
C. eatonii var. clokeyi, C. eatonii var. eatonii, C. eatonii var. eriocephalum, C. eatonii var. murdockii, C. eatonii var. peckii, C. eatonii var. viperinum
Synonyms C. peckii Cnicus hesperius, C. hesperium
Name authority (L. F. Henderson) D. J. Keil: Sida 21: 212. (2004) (Eastwood) D. J. Keil: Sida 21: 212. (2004)
Web links 
Unless otherwise noted, all data comes from the online version of the Flora of North America, who have made most of their content available via a Creative Commons license (CC BY 4.0).



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