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See Cirsium trayci for distinguishing between C. neomexicanum, C. trayci, and C. undulatum.
Cirsium neomexicanum
Cirsium neomexicanum  (New Mexico Thistle)
Asteraceae (Sunflower Family)

Semi-desert, foothills. Shrublands, openings. Spring.
Above Yellow Jacket Canyon, Canyons of the Ancients National Monument, May 8, 2009.

Cirsium neomexicanum is a common site in the arid high desert country of the Southwest. It grows to 60 inches tall from a taproot. Its leaves become progressively smaller higher up the stem until finally they are just minute, spiny bracts.

Cirsium neomexicanum is quite similar to Cirsium tracyi which some consider the same as Cirsium undulatum.  Here is what A Utah Flora has to say about the relationship of C. neomexicanum to C. undulatum:

C. neomexicanum "has long been confused with C. undulatum with which it shares the grayish tomentum, large heads, and tall stature.  They have been separated previously on the basis of glandular development of the dorsal ridge; a feature which is, unfortunately, not diagnostic". 

Asa Gray named C. neomexicanum in 1853 from a specimen collected by Charles Wright in the Organ Mountains of southern New Mexico.

Cirsium neomexicanum

Cirsium tracyi

Cirsium neomexicanum  (New Mexico Thistle)
Asteraceae (Sunflower Family)

Semi-desert, foothills. Shrublands, openings. Spring.
Above Yellow Jacket Canyon, Canyons of the Ancients National Monument, May 8, 2009 &
near Hovenweep Canyon, May 17, 2004.

 

Cirsium neomexicanum

Cirsium neomexicanum

Cirsium neomexicanum  (New Mexico Thistle)
Asteraceae (Sunflower Family)

Semi-desert, foothills. Shrublands, openings. Spring.
Above Yellow Jacket Canyon, Canyons of the Ancients National Monument, May 8, 2009.

The cobwebby hairs at the base of the phyllaries on the surface of the involucre seem to be one diagnostic characteristic of this species.  The shape of the phyllaries is even more accepted as diagnostic. Most botanists agree that the reflexed (bent backward) tips of the phyllaries and the spines separate this species from C. trayci and C. undulatum.

Notice also that the spine-like tips are a different color from the much thicker and green base of the phyllaries.  Utah flora expert, Stanley Welsh, indicates that this is a primary characteristic separating two varieties of this species, the one shown is C. neomexicanum variety utahense and the other with involucral phyllaries green throughout is C. neomexicanum variety neomexicanum. John Kartesz, ultimate authority for plant names on this web site, feels that research does not support the division into varieties.

 

Basal leaves can be 10 inches long and they are quite hairy underneath, moderately so on top.

Range map © John Kartesz,
Floristic Synthesis of North America

State Color Key

Species present in state and native
Species present in state and exotic
Species not present in state

County Color Key

Species present and not rare
Species present and rare
Species extirpated (historic)
Species extinct
Species noxious
Species exotic and present
Native species, but adventive in state
Eradicated
Questionable presence

Range map for Cirsium neomexicanum