Cirsium arizonicum var. chellyense

(R. J. Moore & Frankton) D. J. Keil

Sida 21: 209. 2004.

Common names: Navajo thistle
EndemicConservation concern
Basionym: Cirsium chellyense R. J. Moore & Frankton Canad. J. Bot. 52: 547, plate 2. 1974
Synonyms: Cirsium chuskaense R. J. Moore & Frankton Cirsium navajoense R. J. Moore & Frankton
Treatment appears in FNA Volume 19. Treatment on page 144. Mentioned on page 142.

Stems glabrous or villous to tomentose with septate trichomes. Leaf blades deeply 1–2× divided, (lobes many, narrow, closely spaced), faces glabrous or abaxial villous along midveins with septate trichomes; main marginal spines usually very slender, 5–12 mm; cauline bases usually decurrent as spiny wings to 30 mm. Involucres cylindric to narrowly ovoid. Phyllary spines slender to ± stout, 1–20 mm. Corollas usually reddish purple, 25–32 mm, tubes 7–11, throats 4–7.5 mm, lobes 11–16 mm; style tips 2.5–3.5 mm. 2n = 34 (as C. chuskaense).


Phenology: Flowering summer (Jun–Sep).
Habitat: Desert scrub, grasslands, pine-oak-juniper woodlands, ponderosa pine forests
Elevation: 1600–2800 m

Discussion

Of conservation concern.

R. J. Moore and C. Frankton (1974b) recognized three narrowly defined new species in the Cirsium arizonicum complex, all from a small area in the Defiance Plateau and Chuska Mountains in northeastern Arizona and northwestern New Mexico. The characters used to differentiate these taxa break down when additional specimens are examined, and they are all combined here as a single variety of C. arizonicum.

Selected References

None.

Lower Taxa

None.
David J. Keil +
(R. J. Moore & Frankton) D. J. Keil +
Cirsium chellyense +
Navajo thistle +
Ariz. +  and N.Mex. +
1600–2800 m +
Desert scrub, grasslands, pine-oak-juniper woodlands, ponderosa pine forests +
Flowering summer (Jun–Sep). +
Endemic +  and Conservation concern +
Cirsium chuskaense +  and Cirsium navajoense +
Cirsium arizonicum var. chellyense +
Cirsium arizonicum +
variety +