Kansas Wildflowers and Grasses - Yellow-spine thistle

YELLOW-SPINE THISTLE

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Cirsium ochrocentrum A. Gray

Cimarron National Grassland, Morton County, Kansas

Perennial

Height: 16-60 inches

Family: Asteraceae - Sunflower Family

Flowering Period: June, July, August

Stems:

Erect or ascending, simple or branched distally, densely white-tomentose.

Leaves:

Basal and cauline; blades oblong to narrowly elliptic, 4 to 12 inches long, .8 to 3.2 inches wide, base tapered to winged petiole, strongly decurrent for .4 to .8 inch with spiny wings, margins strongly undulate, coarsely dentate to shallowly or deeply pinnately lobed, lobes triangular, primary spines .16 to .8 inch, abaxial surface densely white-tomentose, adaxial surface thinly gray-tomentose, without appressed prickles.

Inflorescences:

Heads discoid, 1-few in corymb-like arrays. Involucres ovoid to campanulate or hemispheric, .9 to 1.6 inch long, .8 to 1.4 inch wide. Phyllaries many, overlapping in 5-7 series, outer phyllaries ovate, abaxial faces with narrow glutinous ridge, apex bearing spreading spine .16 to .5 inch, inner phyllaries narrowly lanceolate.

Flowers:

Florets 25-200, bisexual, fertile; corollas purple to lavender or whitish, 1.2 to 1.5 inch.

Fruits:

Achenes, brown, .24 to .28, glabrous, apical collar brown; seed 1; pappus white or tawny, .8 to 1.4 inch.

Habitat:

Mixed-grass, shortgrass, and sandsage prairies, pastures

Distribution:

West 2/3 of Kansas

Origin:

Native

Uses:

The Kiowa used flowers of this species, boiled in water, in a preparation to treat burns and skin sores and the Zuni took an infusion of the entire plant to treat syphilis.

Comments:

Cirsium, a Greek name for thistle and ochrocentrum, light yellow and prickle. Our plants belong to var. ochrocentrum.

Yellow-spine thistle phyllaries