New Mexico Thistle

Desert thistle is widespread in the Mojave and Sonoran deserts and ranges into the southern Great Basin desert, western Chihuahuan desert, and into adjacent mountains of Utah, southwestern Colorado, Arizona, and New Mexico.

The name Cirsium utahense has been widely applied in the past to plants that are here recognized as C. inamoenum. S. L. Welsh (1983) treated it as a variety of C. neomexicanum. I have examined the type of C. utahense and can find no basis for distinguishing it from C. neomexicanum at any rank. The desert thistle is closely related to C. occidentale.

Biennials, 40–290 cm; taprooted. Stems usually 1, erect, thinly gray-tomentose, sometimes ± glabrate; branches few–many, usually from above middle, ascending. Leaves: blades oblong–elliptic to oblanceolate, 6–35 × 1.5–7 cm, shallowly to deeply pinnatifid, lobes usually rigidly spreading, undivided or with 1–2 pairs of coarse teeth or lobes, main spines 5–15 mm, faces gray-tomentose, sometimes glabrate; basal often present at flowering, winged-petiolate or sessile, bases tapered, spiny-winged; principal cauline sessile, much reduced distally, bases decurrent as spiny wings less than 5 cm; distal much reduced, ± bractlike, sometimes scarcely more than a cluster of long spines. Heads 1–6 (many on large individuals), borne singly or in corymbiform arrays. Peduncles (2.5–)5–30 cm, bracted. Involucres shallowly hemispheric or campanulate, 2–3 × 2.5–5 cm, arachnoid to ± loosely tomentose, sometimes glabrous. Phyllaries in 7–10 series, imbricate to subequal, linear to narrowly lanceolate, abaxial faces with narrow or no glutinous ridge; outer and mid bodies appressed, entire or minutely spinulose, apices deflexed to spreading or ascending, long, flat, spines spreading to reflexed, 4–15 mm; apices of inner erect, often flexuous, flat. Corollas white to pale lavender or pink, 18–27 mm, tubes 8–14 mm, throats 4–7 mm, lobes 5–9 mm; style tips 4–5 mm. Cypselae dark brown, 5–6 mm, apical collars not differentiated; pappi 15–20 mm. 2n = 30 (as C. utahense), 32; 30 + 1 I.

Cirsium arcuum A. Nelson; C. humboldtense Rydberg; C. neomexicanum var. utahense (Petrak) S. L. Welsh; C. undulatum (Nuttall) Sprengel var. albescens D. C. Eaton; C. utahense Petrak

More info for the term: forb

New Mexico thistle
lavender thistle



TAXONOMY:
The currently accepted scientific name for New Mexico thistle is Cirsium
neomexicanum Gray [8,14,19]. It is a member of the sunflower family
(Asteraceae). The following varieties are recognized [19]:

Cirsium neomexicanum var. neomexicanum
Cirsium neomexicanum var. utahense (Petrak) Welsh


LIFE FORM:
Forb

FEDERAL LEGAL STATUS:
No special status

OTHER STATUS:
NO-ENTRY





DISTRIBUTION AND OCCURRENCE
SPECIES: Cirsium neomexicanum
GENERAL DISTRIBUTION:
New Mexico thistle is found in the desert areas of southern California,
Utah, Colorado, New Mexico, Arizona, and northern Mexico [6,8,14].

New Mexico thistle is found in the desert areas of southern California,
Utah, Colorado, New Mexico, Arizona, and northern Mexico [6,8,14].



Distribution of New Mexico thistle. Map courtesy of USDA, NRCS. 2018. The PLANTS Database.
National Plant Data Team, Greensboro, NC [2018, April 17] [17].

More info for the terms: codominant, shrub, tree

New Mexico thistle is commonly found in creosotebush (Larrea tridentata)
scrub, blackbrush (Coleogyne ramosissima) scrub, shadscale (Atriplex
confertifolia), sagebrush (Artemisia spp.), salt desert shrub, mountain
brush, Joshua tree (Yucca brevifolia) woodlands, and pinyon (Pinus
spp.)-juniper (Juniperus spp.) woodlands [12,16,19]. New Mexico thistle
is not listed as a dominant or codominant in the available literature.

More info for the term: forb

Forb

New Mexico thistle is not a weedy species, unlike many other species of
thistle [5].

Many insect species feed on New Mexico thistle. It hosts three
endophagous insect species. Only the pyralid moth attacks the flowering
heads. The artichoke plume moth attacks the stems and crowns of
New Mexico thistle. Phytophagous insects associated with New Mexico thistle
have been listed [5].

More info on this topic.

New Mexico thistle usually flowers from April to May [5,12].

The currently accepted scientific name for New Mexico thistle is Cirsium
neomexicanum Gray [8,14,19]. It is a member of the sunflower family
(Asteraceae). The following varieties are recognized [19]:

Cirsium neomexicanum var. neomexicanum
Cirsium neomexicanum var. utahense (Petrak) Welsh

Cirsium neomexicanum is a North American species of thistle known by the common names New Mexico thistle, powderpuff thistle, lavender thistle, foss thistle and desert thistle.

This plant is native to the southwestern United States and northwestern Mexico, particularly the Mojave and Sonoran Deserts. It has been found in California, Nevada, Arizona, Sonora, Utah, Colorado, New Mexico, and Texas.