WILDFLOWERS OF NEW MEXICO

With one to many spiny flower heads on one to many hairy, bristly branches, this 20–78-inch tall plant keeps you at a distance. The erect to nodding yellow flower heads are wildly popular with feeding, pollinating, and predator insects, though. Note the phyllaries are densely hairy and appressed against the head. This is a common yellow thistle in NM mountains.

FLOWERS: July–October. Surrounded by a dense network of spiny leaves and silver hairy-fringed phyllaries, the 5/8–1 1/4-inch wide (15–30 mm) flower heads have a dense cluster of 3/8–5/8-inch (11–17 mm) long, thread-like yellow disk flowers and no ray flowers.

LEAVES: Basal leaves reaching 1-foot long develop the first year. Alternate stem leaves clasp the stem; blades highly variable, 4–12-inches long (10–30 cm), oblong to lance-shaped, margins coarsely toothed to deeply dissected into pinnate lobes, variously armed with spines reaching 5/8-inch long (15 mm).

HABITAT: Damp, gravel loam soils of mountain meadows, stream sides, open forests, roadsides; ponderosa pine-Douglas fir, spruce-fir, subalpine forests.

ELEVATION: 7,000–11,500 feet.

RANGE: AZ, CO, NM.

SIMILAR SPECIES: 12 native species of thistles in NM, 5 in 3 or less counties, and two introduced. This is the only high-elevation yellow thistle, though the population in the Sacramento Mts. is sometimes considered a separate species, C. inornatum.  Yellow-spined Thistle, C. ochrocentrum, common up to the pinyon-juniper zone, has pink to white or purple flowers and yellow, 3/8-inch spines on the flower head, and 3/4-inch spines on twisted leaf lobes.

NM COUNTIES: In NM from the Sacramento Mts. north and west in mid- to high-elevation habitats: Bernalillo, Catron, Cibola, Colfax, Grant, Lincoln, Los Alamos, McKinley, Mora, Otero,  Rio Arriba, San Juan, San Miguel, Santa Fe, Sierra, Sandoval, Socorro, Taos, Torrance, Valencia.