Flora of North America species comparison

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Cirsium eatonii var. peckii

Cirsium eatonii var. clokeyi
Cirsium eatonii var. peckii

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

Clokey or Spring Mountains or white-spine thistle
Stems

erect or ascending, stout, 10–150 cm.

erect or ascending, stout, 40–150 cm.
Leaf

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

faces glabrous or nearly so.
Involucres

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

3–5 cm, glabrous or thinly arachnoid tomentose, individual phyllaries evident.
Corollas

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

purple, 24–33 mm, tubes 3.5–7 mm, throats 11–14 mm, lobes 8–12.5 mm.
Phyllaries

green;

outer with few or no lateral spines;

apical spines stout.

green or purplish-tinged;

outer pectinately spiny 1/2 their length with many 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 short-pedunculate in erect, racemiform arrays or sometimes long-pedunculate in openly corymbiform arrays.
Pappi

17–22 mm.

16–18 mm.
2n

= 34 (as C. peckii).

= 34 (as C. clokeyi).

Cirsium eatonii var. peckii

Cirsium eatonii var. clokeyi
Phenology Flowering summer (Jun–Aug). Flowering summer (Jul–Sep).
Habitat Grasslands, juniper woodlands, grass-sagebrush steppes, subalpine slopes, roadsides Gravelly slopes, ravines, montane coniferous forests, subalpine forests, alpine scree
Elevation 1300–2900 m [4300–9500 ft] 2300–3500 m [7500–11500 ft]
Distribution
from FNA
NV; OR
[BONAP county map]
from FNA
NV
[BONAP county map]
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.)

Of conservation concern.

Variety clokeyi is endemic to the Spring Range of Clark County. Its range overlaps that of Cirsium arizonicum var. tenuisectum but no hybrids between the two are known.

(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. 151. 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. eatonii, C. eatonii var. eriocephalum, C. eatonii var. hesperium, C. eatonii var. murdockii, C. eatonii var. peckii, C. eatonii var. viperinum
Synonyms C. peckii C. clokeyi
Name authority (L. F. Henderson) D. J. Keil: Sida 21: 212. (2004) (S. F. Blake) 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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