Cirsium wheeleri

Perennials, slender, 15-60 cm; taprooted with deep-seated root sprouts. Stems 1-few, erect, closely gray-tomentose; branches 0-few, ascending. Leaves: blades lanceolate to narrowly elliptic, 10-25 × 1-4 cm, unlobed and merely spinulose or pinnately lobed about halfway to midveins, often terminal lobes long-tapered, lobes short, lanceolate to triangular, entire to few toothed or lobed, well separated by wide, U-shaped sinuses, main spines slender, 2-5 mm, abaxial faces gray-tomentose, adaxial green, glabrous to thinly tomentose; basal usually present at flowering, winged-petiolate; principal cauline winged-petiolate proximally, mid and distal sessile, progressively reduced distally, bases not or scarcely decurrent, sometimes distal weakly clasping; distalmost often reduced to lanceolate or linear, long-acuminate bracts. Heads 1-6, borne singly or few at branch tips in corymbiform arrays. Peduncles 0-10 cm. Involucres hemispheric to subcylindric, 1.5-2.2 × 1.5-2.5 cm, thinly floccose-tomentose or glabrate. Phyllaries in 6-9 series, imbricate, pale green with darker apices, brownish when dry, lanceolate (outer) to linear-lanceolate (inner), margins of outer entire, abaxial faces with narrow glutinous ridge; outer and middle appressed proximally, apices spreading to ascending, bodies entire or rarely spinulose, spines slender, 3-7 mm; apices of inner often dark purple or blackish, flexuous, scarious, entire to pectinate-fringed, tapered or expanded. Corollas white or pink to pale purple, 20-28 mm, tubes 9-14 mm, throats 5-7.5 mm, lobes 5-10 mm; style tips 2.5-6 mm. Cypselae stramineous with brownish streaks, 6.5-7 mm, apical collars colored like body, narrow; pappi 15-20 mm. 2n = 28.

Flowering summer-fall (Jul-Oct). Coniferous forests, pine-oak, juniper-dominated woodlands, meadows; 1200-2900 m; Ariz., Colo., N.Mex., Tex., Utah; Mexico (Chihuahua, Sonora).

Cirsium wheeleri occurs from the mountains of the Colorado Plateau of central Utah and southwestern Colorado south through the highlands of Arizona and New Mexico to southwestern Texas and northwestern Mexico. The recently described C. wheeleri var. salinense is a minor variant with subentire leaves that is scattered through much of the range of the species.

FNA 2006, Kearney and Peebles 1969, McDougall 1973

Duration: Perennial Nativity: Native Lifeform: Forb/Herb General: Herbaceous annuals, biennials or perennials, stems sparsely to densely gray tomentose, erect, branching apically, the leaves and involucres spiny or prickly. Leaves: Alternate, deeply pinnatifid, the lobes armed with short slender spines, the upper surface green and only sparsely tomentose, the underside densely tomentose. Flowers: Heads discoid, disks pink, lavender, or white, involucres broad, phyllaries in 6-9 series, the outer phyllaries broad, lance-ovate to ovate, with short, slender spines more than 2 mm long, the inner ones purple-tipped and unarmed, erose, dilated and twisted, receptacles densely bristly, the heads usually borne solitary at the branch tips. Fruits: Achenes with brownish streaks, 6-7 mm. Pappus 15-20 mm long. Ecology: Found in coniferous, pine-oak, and open pine forest, and juniper-dominated woodlands, from 5,000-9,000 ft (1524-2743 m); flowering June-October. Distribution: Arizona, Colorado, New Mexico, Texas, and Utah; Mexico. Notes: The keys to this species are the purple or lavender corollas, the heads solitary at the branch and stem tips, the phyllaries broad, lance-ovate or ovate, the inner ones dilated and twisted, with erose tips, the prickles more than 2 mm long. Ethnobotany: Unknown Etymology: Cirsium is Greek for thistle, while wheeleri is named for George Wheeler (1842-1905) who mapped the Great Basin and Mojave deserts. Synonyms: Cirsium blumeri, Cirsium perennans, Cirsium wheeleri var. salinense, Cnicus wheeleri Editor: LCrumbacher 2011