Arkansas ironweed

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Arkansas ironweed heads

Arkansas ironweed

Arkansas ironweed phyllaries

Arkansas ironweed

Arkansas ironweed

Arkansas ironweed leaf

Morphology

Stem

Erect, simple proximally, branched above, glabrous or minutely hispid above.

Leaves

Mostly cauline, alternate; blade linear-lanceolate, 2 to 6 inches long, .2 to 1 inch wide, base wedge-shaped to attenuate, margins serrate to serrate-dentate, tip tapering to long point, surfaces minutely hispid and gland-dotted.

Inflorescence

Heads discoid, in corymb-like to panicle-like arrays; peduncles .8 to 2 inches. Involucres hemispheric, .4 to .6 inch. Phyllaries 50-70 in 5-6 series, narrowly lanceolate to linear, 1/6 to 3/10 inch, apex usually subulate to filiform, sometimes acuminate, usually curled inward.

Flower

Ray florets 0. Disk florets 50-100, corolla reddish-purple, 1/3 to 1/2 inch.

Fruit

Achenes elongate-ellipsoid, 8-10-ribbed, 1/6 to 1/5 inch; pappus brown to purplish-brown, outer scales 10-20, 1/50 to 1/25 inch, inner bristles 20-40, ca. 1/4 inch.

Ecology

Habitat

Moist, open woodlands and floodplain forests, floodplain prairies, stream banks, pastures

Distribution

South half of east quarter of Kansas

Additional Notes