Flora of North America species comparison

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Cirsium eatonii var. peckii

Cirsium eatonii var. viperinum
Cirsium eatonii var. peckii

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

Snake Range thistle
Stems

erect or ascending, stout, 10–150 cm.

erect or ascending, 25–40 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, thinly arachnoid with non-septate trichomes, 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.

lavender to purple, 29–35 mm, tubes 9–12.5 mm, throats 9–12 mm, lobes 9–11 mm.
Phyllaries

green;

outer with few or no lateral spines;

apical spines stout.

green or purplish-tinged;

outer with numerous lateral spines;

apical spines stout.
Heads

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

1–5, subsessile or short-pedunculate, in erect, racemiform or corymbiform arrays.
Pappi

17–22 mm.

20–25 mm.
2n

= 34 (as C. peckii).

Cirsium eatonii var. peckii

Cirsium eatonii var. viperinum
Phenology Flowering summer (Jun–Aug). Flowering summer (Jul–Sep).
Habitat Grasslands, juniper woodlands, grass-sagebrush steppes, subalpine slopes, roadsides Rocky subalpine slopes, open bristlecone pine forests
Elevation 1300–2900 m [4300–9500 ft] 3300–3500 m [10800–11500 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.)

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.

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